Method and apparatus for preparing resin-impregnated structures reinforced by continuous fibers

ABSTRACT

The present invention relates to a method for producing a resin-impregnated structure reinforced by continuous fibers in which a practically endless continuous fiber bundle is dipped in a bath of molten resin and simultaneously passes through a space between a pair of opening pins. The opening pins can be positioned on sides of the bundle so that the continuous fibers are sandwiched by the pins without coming in contact with them. By doing so, the fibers of the bundle can be opened and can be impregnated with the resin. In addition, the foregoing continuous fiber-reinforced resin structure may be cut into pieces having a desired length to provide columnar products.

This is a national stage application of PCT/JP96/03449, filed Nov. 25,1996.

TECHNICAL FIELD

The present invention relates to a method for preparing aresin-impregnated structure, which comprises opening a bundle ofsubstantially endless continuous fibers and then impregnating theresultant open bundle with a resin; a method for producing columnarproducts from the resin-impregnated structure thus prepared; and anapparatus for opening a bundle consisting of continuous fibers and,simultaneously, impregnating it with a resin.

BACKGROUND ART

There have already been known a number of methods and apparatuses forproducing a resin-impregnated structure reinforced with continuousfibers by contacting, in a zigzag pattern, a continuous fiber bundleserving as a reinforcing material with the surfaces of a plurality ofopening means arranged in series within an apparatus for opening andresin-impregnation (or by making them run around the means) andsimultaneously impregnating the opened (or loosed) continuous fiberswith a molten resin. For instance, a variety of techniques are disclosedin the patent publication listed below.

It can be understood from the disclosures thereof that continuous fiberbundles are brought into contact with (opening) pins or (opening) rollsfor opening and resin-impregnation of the continuous fiber bundle, ineither of these techniques. It has been proven that, as a result, thecontinuous fibers are damaged to a substantial extent, that this in turnleads to the formation of fluff and that it is thus difficult to stablyproduce resin-impregnated structures reinforced with continuous fibers.Each publication will hereinafter be described in more detail.

(R1) Japanese Patent Publication No. 63 (1988)-37694 (gazettedspecification) and the Related Written Decision (Trial Case No. 2(1990)-17153).

The gazetted specification and the written decision disclose or proposea method which comprises passing, under tension, reinforcing fiberbundles arranged in a band-like pattern through a spreader whilebringing the bundles into contact with the surface of the spreader, andwhile supplying a thermoplastic polymer having a melt viscosity of lessthan 100 Ns/m² to a nip formed between the reinforcing fiber bundles andthe spreader, to thus impregnate the fiber bundles with the polymer.

(R2) Japanese Patent Laid-Open Publication No. 63 (1988)-264326(gazetted Specification)

In this gazetted specification, there is proposed a method forimpregnation, which comprises arranging or spreading fiber bundles in aweb-like (this term is identical to "band-like") pattern, then coatingthe bundles with a molten resin and thereafter passing the coated fiberbundles through a specific zigzag barrier region within an apparatus foropening and resin-impregnation.

(R3) Japanese Examined Patent Publication No. 5 (1993)-68327 (gazettedspecification)

This gazetted specification proposes a method for impregnation, whichcomprises extruding a molten resin through the tip of a bow head of anextruder and simultaneously passing a series of fibers, under tension,through the bow head while bringing the fibers into contact with the bowhead.

(R4) Japanese Patent Laid-Open Publication No.4 (1992)-278311 (gazettedspecification)

This gazetted specification proposes an impregnation method in which achoking structure is provided in the course of a flow path for fibers inan apparatus for opening and resin-impregnation and the fibers arebrought into contact with the choking structure to thus subject thefibers to opening and to simultaneously impregnate them with a resin.

<Inventors' View on (R1) to (R4)>

These methods can certainly provide resin-impregnated structuresuni-directionally reinforced, which are excellent in resin-impregnationability. In all of these methods, however, the fibers would severely bedamaged since the reinforcing fiber bundles pass through (around) pinsor projected portions while bringing the bundles into contact with thepins or projections. It has been found that, as a result, the methodshave a problem that fluffs are easily formed due to breakage of fibers.The formation of fluffs would impair any stable productivity of theintended resin-impregnated structure and ultimately leads to theinterruption of the apparatus for opening and resin-impregnation.

(R5) Japanese Patent Laid-Open Publication No. 6 (1994)-254857 (gazettedspecification)

This gazetted specification proposes an impregnation method whichcomprises pressing fiber bundle through a die box while pressing itagainst rotatable rolls positioned within the die box in a zigzagpattern to thus induce opening of the fiber bundle and then supplying aresin to opened the fibers, to thereby impregnating it with the resin.

This method is designed so as to reduce the damage to the fibers byrotating the rolls, and permits an increase in the take-off speed to acertain extent (20 m/min). As a result of investigations, however, thefiber bundles are likewise brought into contact with the rolls (orpressed against the rolls), while applying a tension thereto in thismethod as well. Accordingly, it has been found that this method isaccompanied by the easy formation of fluffs and that it is stilldifficult to ensure stable productivity.

(R6) Japanese Patent Laid-Open Publication No. 6 (1994)-91645 (gazettedspecification)

This gazetted specification proposes an impregnation method whichcomprises supplying fiber bundles to an S-shaped die so that the fiberbundles pass through (around) the projected portions in the S-shapedregion under the action of a tension while bringing the bundles intocontact therewith and simultaneously discharging a molten resin throughdischarge openings formed on the tips of the projected portions to thusstepwise impregnate the bundles at three positions.

(R7) Japanese Patent Laid-Open Publication No. 6 (1994)-143440 (gazettedspecification)

This gazetted specification proposes an impregnation method whichcomprises heating the reinforcing fibers in advance, then coating themwith a molten resin and passing the fibers through (around) at least 8projected portions which are arranged alternately while bringing thefibers into contact therewith.

It has been said that these methods described in references (R6) and(R7) permit the achievement of a take-off speed of not less than 20m/min because of the improved means such as the means for stepwiseimpregnation of the reinforcing fibers and for heating the fibers inadvance.

However, it has been found that these methods are often accompanied bythe formation of fluffs. Therefore, it is difficult to ensure stableproductivity. This would be because the fiber bundles are passed through(around) the projected portions under tension thereto while bringing thebundles into contact therewith.

(R8) Japanese Patent Laid-Open Publication No. 63 (1989)-132036(gazetted specification)

This gazetted specification proposes an impregnation method whichcomprises mechanically impregnating reinforcing fiber bundles with aresin by supplying the fiber bundles provided with the resin to thespace formed between upper and lower rolls within an apparatus foropening and resin-impregnation to thus press the bundles.

(R9) Japanese Patent Laid-Open Publication No. 1 (1989)-208118 (gazettedspecification)

This gazetted specification proposes an impregnation method whichcomprises mechanically impregnating reinforcing fiber bundles with aresin by pressing the fiber bundles provided with the resin using upperand lower rolls, i.e., a combination of a convex roll and a concaveroll, within an apparatus for opening and resin-impregnation.

With respect to (R8) and (R9) in each of the foregoing techniques, bothof the opening of continuous fiber bundles and the impregnation of theresulting opened fiber bundles with a resin are performed by thecompressive force acting on the bundles only at the contact pointbetween the upper and lower rolls and accordingly, the contact timebetween the fibers and the rolls is quite short even if using at leasttwo pairs of rolls. As a result, it has been found that there stillremains room for improvement in the impregnating ability. In addition,the fiber bundles are directly pressed by upper and lower rolls, thebundles are thus severely damaged during the opening thereof. As aresult, it has been found that the fibers undergoes form fluffs andproductivity is lowered.

DISCLOSURE OF THE INVENTION

The object of the present invention is to eliminate variousdisadvantages associated with the foregoing conventional techniques andto provide a technique for continuously producing a continuousresin-impregnated structure reinforced with continuous fibers at a hightake-off speed while maintaining high level of stable productivity. Morespecifically, the object of the present invention is to provide aproduction method (hereinafter sometimes referred to as the method ofthe present invention") as well as an apparatus for practicing themethod of the present invention (hereinafter sometimes referred to as"the apparatus of the present invention").

According to the present invention, there is provided a method forproducing a resin-impregnated structure reinforced by continuous fiberssubstantially arranged in a single direction, which comprises subjectinga practically endless continuous fiber bundle to an opening, whileimpregnating the bundle with a molten resin,

wherein the continuous fiber bundle is dipped in a bath of a moltenresin and, simultaneously, the continuous fiber bundle passes throughthe interstice (space) formed between a pair of opening pins positionedon both sides of the bundle in such a manner so that they sandwich thecontinuous fibers without bringing the latter into contact with eitherof the pins to thereby subject the fibers to opening and impregnation ofthe opened fiber bundle.

According to another aspect of the present invention, there is alsoprovided a method for producing a columnar product composed of aresin-impregnated structure reinforced by continuous fibers, which isreinforced by substantially uni-directionally arranged continuous fibersand which is produced by subjecting a practically endless continuousfiber bundle to an opening, while impregnating the bundle with a moltenresin,

wherein the continuous fiber bundle is dipped in a bath of a moltenresin and simultaneously passes through the interstice (space) formedbetween a pair of opening pins positioned on both sides of the bundlesin such a manner that they sandwich the continuous fibers withoutbringing the latter into contact with either of the pins, to therebysubject the fibers to opening and impregnation of the opened fiberhundle with a resin and then the resulting resin-impregnated structurereinforced with unidirectionally arranged continuous fibers is cut intopieces having a desired length.

According to a still another aspect of the present invention, there isprovided an apparatus for producing a resin-impregnated structurereinforced by continuous fibers (an apparatus for opening andresin-impregnation) which comprises reinforcing fibers uni-directionallyarranged and a resin present therebetween, wherein the apparatus atleast comprises:

a zone through which a molten resin formed form a molten resin-supplysystem flows, said molten resin being supplied to the zone through apore for introduction and being stored therein in a predeterminedamount;

an opening for introducing a continuous fiber bundle, said openingsbeing positioned on an end wall or a top plate arranged on the upstreamside of the zone;

at least one pair of opening pins which are approximatelyperpendicularly positioned within the zone so that the continuous fiberbundle introduced therein is immersed in the molten resin and passedtherethrough without coming in contact with the pins;

a shape-determining nozzle positioned on the downstream side along themoving direction of the continuous fiber bundle for drawing the fiberbundle introduced from the opening for introduction to out of the zonewhile passing the bundle through the space formed between the pair ofopening pins without bringing them into contact with the pins; and

a take-off system for the resin-impregnated structure reinforced by thecontinuous fibers, which has drawn from the shape-determining nozzle.

According to a still further aspect of the present invention, there isprovided an apparatus for producing a resin-impregnated structurereinforced by continuous fibers (an apparatus for multiple opening andresin-impregnation) which comprises continuous reinforcing fibersuni-directionally arranged and a resin present therebetween, wherein theapparatus at least comprises:

a zone through which a molten resin formed in a molten resin-supplysystem flows, said molten resin being supplied to the zone through apore for introduction and being stored therein in a predeterminedamount;

at least two openings for introducing continuous fiber bundles, saidopenings being positioned on an end wall or a top plate arranged on theupstream side of the zone for immersion;

at least three opening pins which are approximately perpendicularlypositioned within the zone so that the continuous fiber bundlesintroduced therein are immersed in the molten resin and passedtherethrough without coming in contact with the pins;

a shape-determining nozzle positioned on the downstream side along themoving direction of the continuous fiber bundles so as to draw the fiberbundles introduced through the openings for introduction out of the zonewhile passing the bundles through the spaces formed between the openingpins without bringing them into contact with the pins; and

a take-off system for the resin-impregnated structure reinforced by thecontinuous fibers, which has drawn from the shape-determining nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment for producing a resin-impregnated structure(resin-impregnated structure reinforced by continuous fibers) which isreinforced with uni-directionally arranged continuous fibers andproduced by the method of the present invention and is a schematicvertical cross sectional view of an apparatus according to a firstaspect of the present invention wherein a continuous fiber roving isintroduced into the apparatus through an opening for introducing acontinuous fiber bundle positioned on the end wall on the upstream sideof the apparatus according to the first aspect.

FIG. 2 is a schematic vertical cross sectional view of an embodiment ofan apparatus, according to a second aspect of the present invention, forproducing a resin-impregnated structure reinforced by continuous fibers,which is reinforced with uni-directionally arranged continuous fibersand produced by the method of the present invention and, whereincontinuous fiber rovings are introduced into the apparatus at upperportion of the apparatus on the upstream side.

FIG. 3 shows an apparatus, according to a third aspect of the presentinvention, for producing a resin-impregnated structure reinforced bycontinuous fibers, which is reinforced with uni-directionally arrangedcontinuous fibers and produced by the method of the present inventionand is, more specifically, a schematic vertical cross sectional view ofan apparatus according to an embodiment wherein a continuous fiberroving is introduced into the apparatus through an opening forintroducing a continuous fiber bundle positioned on the end wall on theupstream side of the apparatus and the upper opening pins are parallellyshifted (set aside to one side) towards the upstream side relative tothe lower opening pins.

FIG. 4 is a schematic vertical cross sectional view of a basicembodiment of the opening and resin-impregnation apparatus according tothe present invention for producing resin-impregnated structuresreinforced by continuous fibers, each of which is reinforced withuni-directionally arranged continuous fibers and produced by the methodof the present invention.

FIG. 5 is a schematic vertical cross sectional view of a modifiedembodiment 1 of the opening and resin-impregnation apparatus accordingto the present invention for producing resin-impregnated structuresreinforced by continuous fibers, each of which is reinforced withuni-directionally arranged continuous fibers and produced by the methodof the present invention.

FIG. 6 is a schematic vertical cross sectional view of a modifiedembodiment 2 of the opening and resin-impregnation apparatus accordingto the present invention for producing resin-impregnated structuresreinforced by continuous fibers, each of which is reinforced withuni-directionally arranged continuous fibers and produced by the methodof the present invention.

FIG. 7 is a schematic vertical cross sectional view of a modifiedembodiment 3 of the opening and resin-impregnation apparatus accordingto the present invention for producing resin-impregnated structuresreinforced by continuous fibers, each of which is reinforced withuni-directionally arranged continuous fibers and produced by the methodof the present invention.

FIG. 8 is a schematic longitudinal sectional view of a conventionalopening and resin-impregnation apparatus for producing aresin-impregnated structure reinforced by continuous fibers according tothe method of the Comparative Example wherein a continuous fiber rovingruns around opening pins which comprise only a single series, in azigzag pattern.

FIG. 9 is a schematic longitudinal sectional view of a conventionalopening and resin-impregnation apparatus, according to anotherembodiment, for producing resin-impregnated structures reinforced bycontinuous fibers according to the method of the Comparative Example.

FIG. 10 is a schematic longitudinal sectional view of a conventionalopening and resin-impregnation apparatus, according to a still anotherembodiment, for producing resin-impregnated structures reinforced bycontinuous fibers according to the method of the Comparative Example.

FIG. 11 is a schematic longitudinal sectional view of a conventionalopening and resin-impregnation apparatus, according to a still furtherembodiment, for producing a resin-impregnated structure reinforced bycontinuous fibers, which is reinforced with uni-directionally arrangedcontinuous fibers and produced by the method of the Comparative Example.

FIG. 12 is a schematic longitudinal sectional view of a conventionalopening and resin-impregnation apparatus, according to a furtherembodiment, for producing resin-impregnated structures reinforced bycontinuous fibers according to the method of the Comparative Example.

DETAILED DESCRIPTION

The method for producing a resin-impregnated structure reinforced bycontinuous fibers, the method for producing a columnar products composedof the resin-impregnated structure reinforced by continuous fibers, andthe apparatus used for producing the resin-impregnated structureaccording to the present invention will specifically be described below.

First of all, the method for producing a resin-impregnated resinstructure reinforced by continuous fibers (hereinafter, sometimesreferred to as continuous fiber-reinforced structure) according to thepresent invention will be explained with reference to FIG. 1.

FIG. 1 is a schematic vertical cross sectional view of an apparatus (anopening and resin-impregnation apparatus according to a first aspect ofthe present invention) used for producing a resin-impregnated structurereinforced with uni-directionally arranged continuous fibers, i.e., acontinuous fiber-reinforced resin structure.

In FIG. 1, reference numeral 1 stands for the first opening andresin-impregnation apparatus which is provided with an opening 3 forintroducing a continuous fiber bundle 2 into the apparatus 1 on the endwall on the upstream side with respect to the moving direction of thefiber bundle 2; and a shape-determining nozzle 6 positioned on the otherend wall on the downstream side with respect to the moving direction ofthe continuous fiber bundle 2 in order to draw a continuousfiber-reinforced resin structure 7 which has been subjected to openingand impregnated with a resin out of the apparatus 1.

In the apparatus 1 shown in FIG. 1, the continuous fiberbundle-introduction opening 3 and the shape-determining nozzle 6 areformed in such a manner that the continuous fiber bundle 2 does not comein contact with any opening pin 4 arranged within the apparatus 1 whenthe fiber bundle 2 is subjected to opening and resin-impregnation duringpassing through the apparatus 1 to thus convert the fiber bundle intothe continuous fiber-reinforced resin structure 7.

The continuous fiber bundle-introduction opening 3 used in the apparatus1 preferably has a dimension and a shape which conforms to orcorresponds to those of the cross section of the continuous fiber bundle3, i.e., an oblong rectangle. In addition, if the use of one continuousfiber bundle is insufficient in the continuous fiber content of theresulting continuous fiber-reinforced resin structure, a plurality ofcontinuous fiber bundles 2 arranged lateral and parallel to one anothercan be introduced into this apparatus 1. In such case, the fiberbundle-introduction opening 3 is preferably shaped in an oblongrectangle so that it is adapted for the cross sectional shape of thefiber bundles laterally arranged in a row.

In the first opening and resin-impregnation apparatus 1, the moltenresin formed in a molten resin-supply system (not shown) is introducedinto the first apparatus 1 through an introduction opening 5 formed onthe apparatus 1. An extruder is in general used as such a moltenresin-supply device and commonly used is a screw extruder among others.Various kinds of screw extruders may be used herein and may be either asingle-screw extruder or a multiple-screw extruder such as twin-screwextruder.

The continuous fiber bundle 2 which is introduced into the apparatus 1through the continuous fiber bundle-introduction opening 3 of theapparatus 1 shown in FIG. 1 is "substantially endless". This means thatthe continuous fiber bundle 2 has a shape called a roving when suppliedto the apparatus 1, but, in fact, the length of the roving is of coursefinite and is not a relatively short one having a length of not morethan about 1 m.

In the operation of the apparatus, the final portion of a reel of glassfiber roving (2) may be entangled with and connected to the initialportion of the subsequent roving at a stage immediately before thecomplete consumption of the first reel of roving to thus continue theoperation of the apparatus over a long period of time.

The continuous fiber bundle (2) which is opened according to the methodof this invention includes inorganic continuous fiber bundles, organiccontinuous fiber bundles and composite continuous fiber bundlescomprising inorganic and organic fiber bundles.

Among inorganic continuous fiber bundles, most commonly used are glassfibers and E glass belonging to the silicate has often been used as araw glass material therefor. However, the raw glass material is notrestricted to this specific one and examples thereof of course includefibers comprising potash glass, heat-resistant glass such asborosilicate glass and quartz glass which may be selected depending onthe applications. Other inorganic fibers include, for instance, metalfibers, rock wool and carbon fibers.

On the other hand, examples of organic continuous fibers areall-aromatic polyamide (trade name: Aramid or the like) fibers,all-aromatic polyester (trade name: Kevlar) fibers or Nylon MXD6(copolymer of m-xylylenediamine and adipic acid), which are excellent inphysical properties such as tensile strength, bending (flexural)strength, tensile impact strength and heat resistance (high meltingpoint).

These inorganic and organic continuous fibers are used not only assingle fibers, but also in the form of rovings each obtained by bindinga plurality of single fibers into a bundle with a binder.

The present invention will further be explained with glass continuousfibers, as an example, which have in general been widely used, but othercontinuous fibers as reinforcing materials may be used in the manneridentical to that adopted for the glass continuous fiber, except forcases wherein particular requirements should be satisfied.

Glass continuous fibers used in the present invention as reinforcingmaterials for resins are usual glass rovings and suitably have anaverage fiber diameter ranging from 6 to 30 μm and a number of bundledfibers ranging from 500 to 6000; preferably an average fiber diameterranging from 9 to 23 μm and a number of single fibers (bundled fibers)ranging from 1000 to 4000. At least two such glass rovings may be usedafter subjecting them to yarn doubling, depending on the application.The length of the reinforcing fiber present in the continuousfiber-reinforced resin structure produced by using the opening andresin-impregnation apparatus 1 according to the present invention isapproximately identical to that of the continuous fiber-reinforced resinstructure. In other words, the continuous fiber-reinforced resinstructure 7 is produced by subjecting a substantially endless continuousfiber bundle 2 to opening and impregnation with a resin, and thensubjecting it to pultrusion so that the length of the fibers in theresulting structure are in general identical to that of the structure.

Incidentally, the continuous fiber bundle 2 thus introduced into theopening and resin-impregnation apparatus 1 is opened as it is movedtowards the downstream direction while being gradually converted intoalmost single fibers. The concept of the term "continuous fiber" hereinused generally comprehends "continuous fiber bundle" which is introducedinto the opening and resin-impregnation apparatus 1 and the "continuousfibers" which are in the course of the principal opening stage.

As the molten resin which is charged into the opening andresin-impregnation apparatus 1 and is used for impregnating thecontinuous fibers 2 while the continuous fiber bundles 2 are subjectedto opening, a thermoplastic resin can suitably be used. Examples of suchthermoplastic resins usable herein are crystalline thermoplastic resinssuch as polyolefin resins, polyamide resins (nylons) and polyesterresins. These crystalline thermoplastic resins may be used alone or inany combination thereof. Among these crystalline thermoplastic resins,preferred are polyolefin resins for the usual applications from theviewpoint of their properties and prices. The concept of the term"polyolefin resin" herein used comprehends, for instance, crystallinehomopolymers or copolymers of α-olefins usually having about 2 to 10carbon atoms; compositions each comprising at least two such crystallinehomopolymers; compositions each comprising at least two such crystallinecopolymers; or compositions each comprising at least one suchcrystalline homopolymer and at least one such crystalline copolymer.

Examples of α-olefins having 2 to 10 carbon atoms include ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octeneand 1-decene, which may be homopolymerized or at least two of which maybe copolymerized.

Among these crystalline polyolefins (so-called "poly-α-olefins"),crystalline polypropylene resins are most widely used from the viewpointof practical use. Moreover, if the continuous fiber-reinforced resinstructure produced according to the present invention is used at a lowtemperature, preferred are polyethylene resins rather than polypropyleneresins, while if it is used under high temperature conditions, suitablyused are poly-4-methyl-1-pentene resins. Furthermore, if it is usedunder conditions wherein the temperature is higher than 200° C.,suitably used are various kinds of polyamide resins or polyester resinshaving high heat resistance. Examples of polyamide resins usable hereinare ring opening-addition polymerized type nylons such as 6-nylon andpoly-condensed type nylons such as 6,6-nylon. In addition, if thestructure must have more higher heat resistance, there have been used,for instance, semi-aromatic polyamide resins or all-aromatic polyamideresins (aramid resins). Examples of preferred semi-aromatic polyamideresins are copolycondensed polymers of m-xylylenediamine and adipic acid(so-called "nylon MXD6") and examples of preferred all-aromaticpolyamides are copolycondensed polymers of m-xylylenediamine andterephthalic acid (for instance, those distributed under the trade nameof "Kelimide").

In addition, the polyesters (resins) used in the present invention arecopolycondensates of aliphatic diols and aromatic dicarboxylic acids andmost usually used are, for instance, copolycondensates of ethyleneglycol (or "ethylene oxide (oxilane)) with terephthalic acid("polyethylene terephthalates" (abbreviated as "PET")). Examples ofpolyesters having more higher heat resistance are copolycondensates ofterephthalic acid wherein 1,4-butanediol is substituted for ethyleneglycol as the aliphatic diol component ("poly-1,4-butanediolterephthalate" (abbreviated as "PBT")).

The foregoing first opening and resin-impregnation apparatus 1 isprovided with at least one pair of opening pins 41 arranged therein atdesired distances so that the continuous fiber bundle 2 is not broughtinto contact with these pins.

The fixed opening pins 4 constituting the paired opening pins 41 haveelements and properties suitable for functioning, so that the flow ofthe resin entrained by the continuous fiber bundle 2 is dammed up tothus generate a turbulent flow of the resin. In FIG. 1, the apparatus isprovided with fixed opening pins each having a circular cross-sectionperpendicular to the longitudinal axis of the opening pin 4. In additionto the foregoing circular shape, the sectional shape of the fixedopening pins 4 may be, for instance, a triangular or quadrangular shapewherein the tip thereof may be cut off and rounded to give a convexpolygonal shape such as a so-called "rounded polygonal shape". In thisregard, the cross-sectional shape may likewise be a polygonal shapehaving rather a large number of apexes such as pentagonal, hexagonal oroctagonal shape among others or effectively used herein are polygonalshapes having cross sectional shapes which permit the damming up of theresin flow by the widest possible area of the pin.

The pin may have a polygonal cross-section such as hexagonal, octagonalor dodecagonal one whose apexes (or edges) portions are rounded off,i.e., a cross-section of a so-called "rounded polygonal shape", inaddition to the circular shape. Thus, the pin may have a cross-sectionalshape which permits the damming up of the resin flow by the widestpossible area of the pin.

The surface of the fixed opening pin 4 is not needed to be finished to aparticularly smooth one and the degree of surface smoothness attained bysimply cutting a rod with, for instance, a lathe. A lathe may besufficient in most of cases. Incidentally, in cases wherein fixedopening pins 4 having a triangular cross section is adopted, an anglebar may be substituted for the body cut out from a rod by arranging suchthat the edge thereof serves as the top edge (i.e., in the form of aroof).

FIG. 1 shows an embodiment which includes three opening regions withinthe apparatus 1 comprising three sets of paired opening pins 41 eachpair comprising fixed opening pins 41u and 41d, opening pins 42u and 42dor fixed opening pins 43u and 43d which make corresponding opening pinpairs 41.

The paired opening pins 41 are arranged starting from the upstream sidealong the moving direction of the continuous fiber bundle 2 so thatfixed opening pins 4 which make a pair are positioned at the upper andlower side of the continuous fiber bundle, which pins 41 areapproximately perpendicular to the running direction of the fiberbundle. These opening pins 4 are in general fixed to a side wall (notshown) of the opening and resin-impregnation apparatus 1, which wall isapproximately perpendicular to the running direction of the fiber bundleand is parallel to the moving direction of the continuous fiber bundle2.

In the opening and resin-impregnation apparatus according to the presentinvention, the terms "upper and lower, right and left and in front andin rear" or the like are simply used for convenience of the explanationof the present invention with referring to the accompanying drawings anddo not represent any absolute relation of positions in the apparatus 1.

Moreover, the term "opening stage" herein used means the stage extendingfrom the position at which the continuous fiber bundle introduced intothe opening and resin-impregnation apparatus in the manner as discussedabove initially passes through the interstice formed between the pairedopening pins to the position at which the fiber bundle graduallysubjected to the opening passes through the final paired opening pins.

The continuous fiber bundle 2 runs through the interstice formed betweentwo such fixed opening pins 4 without coming in contact with both ofthese fixed opening pins 4 and moves in the molten resin towards ashape-determining nozzle 6. Thus, the continuous fibers initially in theform of a bundle is gradually subjected to opening during the downwardmovement of the continuous fiber bundle 2 towards the shape-determiningnozzle 6. The opening and resin-impregnation apparatus 1 is filled witha molten resin and the resin penetrates into the opened continuousfibers as the opening of the fiber bundle 2 proceeds.

Regarding the fixed opening pins, each opening pin pair comprises a setof two pins arranged upper and lower positions. In FIG. 1, the pairedopening pins 41 with which the continuous fiber bundle initiallyencounters includes a fixed opening pin 41u positioned above the fiberbundle 2 and a fixed opening pin 41d positioned below the fiber bundle2. These fixed opening pins 41u and 41d form an interstice therebetweenand the interstice is designed in such a manner that the fiber bundle 2can pass through the same without coming in contact with these pins 41uand 41d.

In this respect, these fixed opening pins 41u and 41d arranged so thatthe length (H: hereinafter also referred to as "definition distance") ofthe perpendicular line connecting a plane ("upper plane (Pu)") on thesurface of the upper fixed opening pin 41u which is nearest to thecontinuous fiber bundle and approximately parallel to the fiber bundleand a plane ("lower plane (Pd)") on the surface of the lower fixedopening pin 41d which is nearest to the continuous fiber bundle andapproximately parallel to the fiber bundle, and an average diameter (D)of single fibers constituting the continuous fiber bundle in generalsatisfy the relation: 10 D≦H≦500 D, preferably 20 D≦H≦300 D.

Moreover, when providing a plurality of the paired opening pins as shownin FIG. 1, the definition distances (H) between the fixed opening pins42u and 42d and between the fixed opening pins 43u and 43d are set atvalues so that each definition distance and the average diameter (D) ofsingle fibers constituting the continuous fiber bundle (2) fulfills thefollowing relation: 10 D≦H≦500 D, preferably 20 D≦H≦300 D.

In the opening step of the present invention, the continuous fiberbundle 2 to be subjected to opening is impregnated with a molten resinwhile passing through a bath filled with the molten resin (a reservoirzone) without coming in contact with the paired opening pins 41 as themeans for opening. To this end, it is important that the definitiondistance (H) of the paired opening pins 41 is sufficiently larger thanthe average diameter (D) of the single fibers formed by the opening. Ifthe foregoing requirement is not satisfied, it can become considerablydifficult that the continuous fiber bundle (2) passes through theinterstice formed between the opening pins constituting the pairedopening pins 41 without coming in contact with these opening pins.

If the continuous fiber bundles are glass rovings each having a bundlingnumber of 4000 and the diameter (D) of the single fiber constituting thefiber bundle is assumed to be, for instance, about 17 μm, the definitiondistance (H) in general falls within the range: 170 μm≦H≦8500 μm andpreferably 340 μm≦H≦5100 μm. There have of course been proposed avariety of continuous fiber bundle products having bundling numbers andaverage diameters of single fibers, at least either of which isdifferent from those specified above and there have rather been knownmany products having an average diameter (D) of single fiber rangingfrom 9 to 23 μm and a bundling number ranging from 1000 to 4000.

The continuous fiber bundle 2 is subjected to opening by passing throughthe opening pin pair at least one time without coming in contact withthe fixed opening pins.

FIG. 1 shows an embodiment wherein three pairs of opening pins 41 arearranged, starting from the upstream side, along the moving direction ofthe continuous fiber bundle 2. In such apparatus 1, the continuous fiberbundle 2 is gradually subjected to opening by passing through theinterstices between these three paired opening pins 3 without coming incontact with the fixed opening pins 41u, 41d, 42u, 42d, 43u, 43d. Inthis respect, the continuous fiber bundle 2 is impregnated with a moltenresin charged in the apparatus 1 while the fiber bundle gradually passesthrough the opening stage and thus, a continuous fiber-reinforced resinstructure 7 according to the present invention is formed.

In the opening and resin-impregnation apparatus 1 as is shown in FIG. 1,the paired opening pins 41 preferably comprises the upper opening pin41u and the lower opening pin 41d which are arranged in such a mannerthat they sandwich the continuous fiber bundle 2 from the upper andlower sides thereof and that they are free of any rotation and alsopreferably, at least three such pairs are systematically providedtowards the downstream direction.

Furthermore, at least five such paired opening pins are preferablyprovided in order to improve the degree of opening and the ability ofthe opened continuous fiber to be impregnated with the resin.

The minimum distance between each neighboring paired opening pins in theforegoing production apparatus is not particularly restricted, but theminimum distance (for instance, the minimum distance between the pairedopening pins comprising fixed opening pin 41u and 41d and the pairedopening pins comprising fixed opening pin 42u and 42d) is in general setat a level of not less than 15 mm, preferably not less than 25 mm whentaking a case wherein each of the opening pins is a rod having acircular section and a diameter of 10 mm by way of example.

There has conventionally been adopted a method in which a continuousfiber bundle 2 is brought into contact with opening pins 4 when thefiber bundle 2 (roving) is subjected to opening. In the presentinvention, however, the continuous fiber bundle 2 is opened whilepassing it in a molten resin-storing zone through the interstices formedbetween the paired opening pins 4u and 4d which are free of any rotationwithout coming in contact with the surface of the opening pins at all.The resin penetrates into the spaces formed between the openedcontinuous fibers along with the opening of the continuous fiber.

The continuous fiber bundle 2 is sufficiently subjected to openingalthough the fiber bundle 2 and the opened continuous fibers only runnear the fixed opening pins 4 without coming in contact with the same.This fact contradicts conventional wisdom. Although the openingmechanism has not yet been elucidated, it is recognized that the moltenresin rises on the upstream side of the fixed opening pins 4 of a pairduring the passage of the continuous fiber bundle 2 through the openingand resin-impregnation apparatus 1.

It would be supposed, from this fact, that the movement of the fiberbundle 2 is accompanied by a flow of the molten resin near the surfacethereof along the moving direction of the bundle. Simultaneously, theresin flow thus generated collides with the upstream side walls of thepaired upper and lower fixed opening pins 4u and 4d, thus causes achange in the flowing direction and goes away from the fiber bundle togenerate a vortex flow in which the horizontal axis serves as the centerthereof.

If taking the fixed opening pin 4u as an example, the resin flowgenerates a counterclockwise vortex flow directed upward and comes backto the upstream side and then descends and almost perpendicularlycollides with the continuous fiber bundle 2, while the behavior of theresin flow near the lower fixed opening pin 4u is contrary to that nearthe upper opening pin. More specifically, the resin flow which collideswith the lower fixed opening pin 4u generates a clockwise vortex flow,comes back to the upstream side, then ascends and approximately upwardlycollides with the continuous fiber bundle 2. Thus, it would beinterpreted that the latter resin flow serves to open the fiber bundle 2together with the resin flow which downwardly collides with the bundle.

Incidentally, even in the multiple opening and resin-impregnationapparatus in which at least three pairs of fixed opening pins 4 (eachpair comprises a combination of upper and lower pins) as will bedetailed below, it would be considered that the same vortex flowsdescribed above may be generated near each paired opening pins and theopening of the continuous fiber bundle is thus carried out by the actionof the vortex flows.

More specifically, the following requirements can be fulfilled in themethod of the present invention:

The continuous fiber bundle passes through the interstice formed betweenthe opening pins without coming in contact with the pins during theopening stage;

The ratio of the vertical distance (or definition distance), i.e., thedistance between the pins making a pair to the average diameter of thecontinuous fiber may be set at a specific range; and

The continuous fiber bundle can approximately linearly run during theopening without any change in the moving direction.

As has been described above, in the present invention the non-contactopening and impregnation unexpectedly permit the achievement of highimpregnating ability and high productibity even in high speed openingand high speed taking-off which have never been considered to berealized easily as a result of various drawbacks such as fluffing.

As has been discussed above in detail, the continuous fiber-reinforcedresin structure and the columnar product according to the presentinvention can be produced using the first opening and resin-impregnationapparatus, shown in FIG. 1, according to the present invention, but thecontinuous fiber-reinforced resin structure may likewise be producedusing the second opening and resin-impregnation apparatus 11, shown inFIG. 2, according to the present invention.

In FIG. 2, the reference numeral 11 represents this second opening andresin-impregnation apparatus and this apparatus is provided with anopening 3 for introducing a continuous fiber bundle 2 into the secondapparatus 11 on an upstream top plate in the moving direction of thefiber bundle 2.

The moving direction of the continuous fiber bundle 2 introduced intothe second opening and resin-impregnation apparatus 11 through thecontinuous fiber bundle-introducing opening 3 is changed by a turningpin 8 so that the fiber bundle 2 passes through the interstice formedbetween the upper and lower opening pins 41u and 41d without coming incontact with these fixed opening pins 4 and is taken out through theshape-determining nozzle 6 in the form of a continuous fiber-reinforcedresin structure 7.

In FIG. 2, the position of each paired opening pins and the arrangementof the common members are the same as those depicted on FIG. 1 and allthe members which are common to those shown in FIG. 1 bear the samereference numerals.

Moreover, in the opening and resin-impregnation apparatus 11 of thepresent invention, the paired fixed opening pins 4 are not necessarilyperpendicularly arranged, as shown in FIG. 3.

As has been shown in FIG. 3, for instance, the paired fixed opening pinsmay likewise sandwich the continuous fiber bundle 2 in such a mannerthat the upper fixed opening pin 41u constituting the opening pin pair41 sandwiching from the upper and lower directions, the fiber bundle 2which moves in the horizontal direction, while maintaining itsapproximately horizontal condition, comes in contact with the fiberbundle 2 from the downward direction at a position inclined to theupstream side, while the lower fixed opening pin 41d comes in contactwith the fiber bundle 2 from the upward direction at a position inclinedto the downstream side.

In the same manner, the upper fixed opening pins 42u and 43u as well asthe lower fixed opening pins 42d and 43d are arranged. In the presentinvention, such a sandwiched state of the fiber bundle 2 is alsoreferred to as "oblique sandwiching".

Thus, when two fixed opening pins 4u and 4d are arranged such that thefiber bundle 2 is obliquely sandwiched in this way, the upper and lowerfixed opening pins 41u and 41d, as shown in FIG. 3, are arranged so thatthe plane perpendicular to that on which the fiber bundle 2 movesintersects the plane u-d including both the central axes of the fixedopening pins 41u and 41d at an angle which satisfies the followingrelation: usually -45°≦α≦+45° and preferably -35°≦α≦+35°.

Therefore, as an embodiment wherein the fixed opening pin 4 is arrangedso as to obliquely sandwich the continuous fiber bundle 2, by contrastto the embodiment shown in FIG. 3, the lower fixed opening pin 41d ispositioned on the upstream side of the molten resin flow generated bythe movement of the fiber bundle 2, while the upper fixed opening pin41u is positioned on the downstream side of the molten resin flowgenerated by the movement of the fiber bundle 2. In this case, otherfixed opening pins 42d, 43d as well as the fixed opening pins 42u, 43uare usually arranged in the same manner.

Moreover, in an extended embodiment, every fixed opening pins 4 may bearranged such that the upper fixed opening pin 41u and the lower fixedopening pin 41d in one paired opening pins 41 sandwich the fiber bundle2 from the upstream and downstream sides thereof respectively, that theupper and lower fixed opening pins 42u, 42d in another paired openingpins 42 sandwich the fiber bundle 2 from the downstream and upstreamsides thereof respectively and that the upper and lower fixed openingpins 43u, 43d in the third paired opening pins 43 sandwich the fiberbundle 2 from the directions just above and just below the bundle 2respectively. In FIGS. 2 and 3, all the members which are common tothose depicted on FIG. 1 bear the same reference numerals.

As has been described above, the continuous fiber-reinforced resinstructure 7 of the present invention can be produced using, forinstance, the opening and resin-impregnation apparatus shown in FIGS. 1to 3, but a multiple opening and resin-impregnation apparatus as will bedetailed below may be used in the production method of the continuousfiber-reinforced resin structure 7 of the present invention.

The multiple opening and resin-impregnation apparatus used in the methodof the present invention comprises at least:

a zone through which a molten resin formed in a molten resin-supplysystem flows, said molten resin haing supplied to the zone through apore for introduction and stored therein in a predetermined amount;

at least two openings for introducing continuous fiber bundles, which ispositioned on an end wall or a top plate arranged on the upstream sideof the zone for immersion;

at least three (three pairs of) fixed opening pins 4, said pins beingapproximately perpendicularly positioned within the zone so that thecontinuous fiber bundles 2 introduced therein are immersed in the moltenresin and pass therethrough without coming in contact with the pins;

a shape-determining nozzle 6 positioned on the downstream side along themoving direction of the continuous fiber bundles 2 for drawing the fiberbundles 2 introduced from the openings 3 for introduction to out of thezone while passing the bundles through the interstices formed betweenthe opening pins 4 without coming them into contact with the pins 4; and

a take-off system for the continuous fiber-reinforced resin structure 7drawn from the shape-determining nozzle.

FIG. 4 is a schematic cross sectional view of an embodiment of the firstmultiple opening and resin-impregnation apparatus.

A plurality of continuous fiber bundles 2u1 and 2d1 are introduced intothe multiple opening and resin-impregnation apparatus 1 (abbreviated as"multiple apparatus 1") according to the present invention as shown inFIG. 4.

In FIG. 4, the upper continuous fiber bundle 2u1 upward positioned isintroduced into the multiple opening and resin-impregnation apparatus 1through an upper continuous fiber bundle-introducing opening 3u1positioned on the left side wall 1wl of the apparatus 1, while the lowercontinuous fiber bundle 2d1 downward positioned is introduced into themultiple opening and resin-impregnation apparatus 1 through a lowercontinuous fiber bundle-introducing opening 3u1 positioned below theupper continuous fiber bundle-introducing opening 3u1 on the left sidewall 1wl of the apparatus 1. The continuous fiber bundles 2u1 and 2d1used in this embodiment may be the same as those used in the opening andresin-impregnation apparatus shown in FIG. 1. In addition, the shapes,structures, materials, sizes or the like of the fixed opening pins 4 areidentical to those discussed above in connection with the embodimentshown in FIG. 1.

The multiple opening and resin-impregnation apparatus 1 is filled with amolten resin as has been described above in connection with theembodiment shown in FIG. 1. The molten resin charged therein is obtainedin a molten resin-supply system (not shown) and fed to the multipleapparatus 1 through the resin-introducing opening 5.

This multiple opening and resin-impregnation apparatus 1 is providedwith a plurality of fixed opening pins 4 which are approximatelyperpendicularly aligned. More specifically, the multiple opening andresin-impregnation apparatus 1 comprises upper fixed opening pins 4u1,middle opening pins 4m1 and lower fixed opening pins 4d1 which areapproximately aligned in vertical lines. In this connection, the upperfixed opening pins 4u1 and the middle opening pins 4m1 are arranged soas to form an interstice through which the upper continuous fiber bundle2u1 can pass without coming in contact with these pins. The middle fixedopening pin 4m1 and the lower fixed opening pin 4d1 are positioned so asto pass the lower continuous fiber bundle 2d1 can pass without coming incontact with these pins. Regarding the upper continuous fiber bundle2u1, the upper fixed opening pin 4u1 and the middle opening pin 4m1 makea pair and perform the opening of the upper continuous fiber bundle 2u1.

With respect to the lower continuous fiber bundle 2d1, on the otherhand, the middle fixed opening pin 4ml and the lower fixed opening pin4d1 make a pair and perform the opening of the lower continuous fiberbundle 2d1 which passes through the interstice formed between these twofixed opening pins.

The fixed opening pins 4 fitted to the multiple apparatus 1 of thepresent invention is in general a tubular or rod-like body (hereinaftercomprehensively referred to as "rod-like body") such as an approximatelycylindrical (hollow) or columnar (solid) body. The generating lines ofthese fixed opening pins 4 are in general approximately straight lines.Moreover, the diameter of the fixed opening pin 4 is in general in therange of from about 5 to 50 mm and the length thereof may be, inprinciple, identical to the lateral inside dimension of the multipleopening and resin-impregnation apparatus 1 of the present invention andmay range, for instance, from about 200 to 500 mm, provided that thelength of the fixed opening pin 4 is also influenced by the number ofrovings arranged in parallel (the number of rovings simultaneouslyintroduced into the apparatus, which are arranged in a horizontal row).

Moreover, the upper fixed opening pin 4u, the middle fixed opening pin4m and the lower fixed opening pin 4d which make pairs are fixed in sucha manner that they do not rotate as the continuous fiber bundles 2u1,2d1 proceed. The fact that these fixed opening pins 4u, 4m and 4d arenon-rotatably fixed to the apparatus is very important to generate avortex flow of the molten resin at the upstream side.

However, when a more vigorous vortex flow should be generated at theupstream of the paired opening pins comprising the upper fixed openingpin 4u and the middle fixed opening pin 4m and of the paired openingpins comprising the middle fixed opening pin 4m and the lower fixedopening pin 4d, these fixed opening pins 4u, 4m and 4d are rotated at anangular velocity sufficient for generating a vector opposite to that ofthe progressive vector of the continuous fiber bundles 2u1, 2d1 and suchembodiments also fall within the range of the present invention.

In the multiple opening and resin-impregnation apparatus 1 of thepresent invention, the continuous fiber bundles 2u1 and 2d1 each isintroduced into the apparatus from the right hand side (downstream side)thereof through the corresponding continuous fiber bundle-introducingopening 3ul or 3dl positioned on the left side wall 1wL in FIG. 4, thefiber bundles pass through the passage sandwiched by two upper and lowerfixed opening pins 4ul and 4ml which make a pair together or the passagesandwiched by fixed opening pins 4ml and 4dl which make a pair togetherand thus are subjected to opening, without coming in contact with thefixed opening pins 4ul, 4ml and 4dl and the molten resin penetrates intoand/or between a number of continuous fibers thus separated. In thisconnection, if the upper and lower opening pins 4ul and 4dl are bothrotatable, the middle fixed opening pin 4ml is in general fixed so asnot to cause rotational motion.

In the principal opening stage in the multiple opening andresin-impregnation apparatus 1 of the present invention, the continuousfiber bundles 2ul and 2dl to be subjected to opening pass through themolten resin without coming in contact with any fixed opening pin 4 andare spaced apart a distance, falling within a specific range, fromeither of the fixed opening pins 4 constituting a paired opening pins.It is preferred that the interstice formed between a pair of openingpins through which the continuous fiber bundle 2ul or 2dl passes fallswithin a desired range in order that the opening of the fiber bundlesare ensured although the continuous fiber bundles 2 do not come incontact with any fixed opening pin 4 as has been described above. Thevertical distance (H) between the pins constituting a specific pairedopening pins is herein specified as "definition distance (H)". Thedefinition distance (H) and the average diameter (D) of the singlefibers constituting the continuous fiber bundle 2 to be subjected toopening preferably satisfy the following relation represented by aninequality.

That is, the following relation: usually 10 D≦H≦500 D, preferably 20D≦H≦300 D is established between the definition distance H and theaverage diameter D of the continuous fiber.

In the multiple opening and resin-impregnation apparatus 1 of thepresent invention, if selecting three stages of opening pins 4u, 4m and4d which are arranged approximately in the vertical direction, the upperand middle fixed opening pins 4u and 4m make a pair and the middle andlower fixed opening pins 4m and 4d make a pair. In this case, thedefinition distance (Hu) of the former pair and that (Hd) of the latterpair may be the same or different. The effect of the present invention,i.e., "the opening and impregnation without causing any fluffing" canoften be accomplished certainly in any pair by reducing the distance (H)as the opening of the continuous fiber bundle 2 proceeds.

In FIG. 4, there is shown an embodiment in which three (or three stages)of fixed opening pins 4 are arranged in the vertical direction. Thefixed opening pins 4 arranged in the vertical direction may of course benot less than 3 (or 3 stages), preferably 3 to 5.

In FIG. 4, three (odd number) of the fixed opening pins 4 is arranged inthe vertical direction and therefore, the middle fixed opening pin 4mlserves not only as a lower fixed opening pin for constituting a pair forthe upper continuous fiber bundle 2ul, but also as an upper fixedopening pin for constituting a pair for the lower continuous fiberbundle 2dl, but if even number of fixed opening pins 4 are arranged inthe vertical direction, opening pin pairs each may be formed from twospecially designed fixed opening pins.

The embodiment shown in FIG. 4 corresponds to a multiple opening andresin-impregnation apparatus 1 in which three fixed opening pins arearranged in the vertical direction and two additional groups of fixedopening pins wherein the pins in each group are arranged along thevertical direction to thus give paired opening pins are provided on thedownstream side along the moving direction of the continuous fiberbundle 2. The second group of the fixed opening pins comprise threefixed opening pins represented by 4u2, 4m2 and 4d2 and the third groupof the fixed opening pins comprise three fixed opening pins representedby 4u3, 4m3 and 4d3. In these second and third groups of the fixedopening pins, the mounting positions for every fixed opening pins or thelike are similar to those described above in connection with the firstgroup of the fixed opening pins. FIG. 4 shows a multiple opening andresin-impregnation apparatus 1 provided with three groups of fixedopening pins, but the apparatus may of course be provided with 1 to 3groups of fixed opening pins or not less than 4 groups, preferably notless than 5 groups of fixed opening pins.

The continuous fiber bundles 2u1 and 2d1 which have been subjected toopening by passing through the interstices (H) formed between theopening pins arranged in the foregoing manner and simultaneouslyimpregnated with a resin are taken off through two stages, i.e., upperand lower shape-determining nozzles 6ul and 6dl formed on the downstreamend wall 1wR of the multiple opening and resin-impregnation apparatus 1to thus give continuous fiber-reinforced resin structures 7ul and 7dl.

As seen from FIG. 4, the multiple opening and resin-impregnationapparatus 1 used in the method of the present invention comprises areservoir part which is composed of an upstream end wall 1wL, adownstream end wall 1wR, right and left side walls thereof (not shown),a bottom plate 1wB and a top plate 1wA; a plurality of continuous fiberbundle-introducing opening 3ul and 3d1 formed on the upstream end wall1wL; paired opening pins comprising at least three fixed opening pins4ul, 4ml and 4dl arranged along the vertical direction; andshape-determining nozzles 6ul and 6dl formed on the downstream end wall1wR for taking off the continuous fiber bundles 2 which is subjected toopening by passing through the paired opening pins and is impregnatedwith a resin. In the multiple opening and resin-impregnation apparatus11 of the present invention, the continuous fiber bundle-introducingopenings 3 may be formed on the top plate 1wA as shown in FIG. 5. If thecontinuous fiber bundle-introducing openings 3 are formed on the topplate 1wA, the moving direction of the continuous fiber bundles 2introduced into the apparatus must be changed before the fiber bundles 2encounter the initial paired opening pins to a direction in which thebundles do not come in contact with any fixed opening pin in order totake off the opened (filamentated) fiber bundles 2 through theshape-determining nozzles 6 after the opening of the fiber bundle bypassing through the interstices formed between the fixed opening pins 4without bringing into contact with any pin 4.

In FIG. 5, the reference numeral 11 represents this second multipleopening and resin-impregnation apparastus and the apparastus is providedwith openings 3 for introducing the continuous fiber bundles 2ul and 2dlinto the second multiple opening and resin-impregnation apparastus 11formed on the top plate 1wA on the upstream side along the movingdirection of the fiber bundles 2.

Then the moving direction of the continuous fiber bundles 2ul and 2dlintroduced into the second multiple opening and resin-impregnationapparatus 11 through the continuous fiber bundle-introducing opening 3is changed by turning pins 8u and 8d so that they pass through theinterstices formed between the upper and middle fixed opening pins 4uland 4ml and between the middle and lower fixed opening pins 4ml and 4dlwithout coming in contact with these pins and is then taken off throughthe shape-determining nozzles 6ul and 6dl. The number of these turningpins 8 is in general determined depending on the number of thecorresponding continuous fiber bundles 2 introduced into the multipleapparatus 11.

Moreover, FIG. 6 shows a third multiple opening and resin-impregnationapparatus 12 which is provided with a plurality of continuous fiberbundle-introducing openings 3ul and 3dl formed on the upstream end wall1wL, wherein the continuous fiber bundles 2ul and 2dl introduced intothe apparatus in the same manner explained above in connection with theapparatus shown in FIG. 4 is subjected to opening by passing through theapparatus without coming in contact with any fixed opening pins 4 andsimultaneously impregnated with a resin and then a single continuousfiber-reinforced resin structure 71 is taken off in the form of a unitedsingle body through a shape-determining nozzle 61.

In case of the third multiple opening and resin-impregnation apparatus12, it is preferred to fit downsteam turning pins 9ul and 9dl to theapparatus on the downstream side of the final fixed opening pins 4u3,4m3 and 4d3 so that the continuous fiber bundles 2ul and 2dl can passthrough the interstices formed between the paired opening pinscomprising fixed opening pins 41, 42 and 43 without coming in contactwith any fixed opening pins 4 and then taken off the fiber bundles as asingle continuous fiber-reinforced resin structure 71 through theshape-determining nozzle 61.

Further, in the multiple opening and resin-impregnation apparatus or thelike of the present invention, the fixed opening pins 4u, 4m and 4dwhich make a pair do not need to be arranged in the directionperpendicular to the moving direction of the continuous fiber bundles 2.

FIG. 7 shows a fourth multiple opening and resin-impregnation apparatus13 corresponding to the embodiment wherein the fixed opening pins 4 arearranged at positions which are shifted (deviate) from the positions ona plane perpendicular to the moving direction of the continuous fiberbundles 2.

More specifically, in FIG. 7, in paired opening pins 4, two fixedopening pins 41 makes a pair and these fixed opening pins 4ul, 4ml and4dl are in general non-rotatably (free of rotational motion) fixed tothe side wall of the opening and resin-impregnation apparatus almostperpendicularly thereto. In other words, the mounting positions of thesefixed opening pins 4ul, 4ml and 4dl which make the opening pin pairs areselected in such a manner that the central axes of the fixed openingpins 4 are symmetric with respect to the continuous fiber bundles 2uland 2dl within the plane approximately perpendicular to the plane onwhich the fiber bundles move.

However, it is sufficient to arrange these paired opening pins in such amanner that the fiber bundles 2ul and 2dl do not come in contact withany fixed opening pins 4 and the opening of the fiber bundles 2ul and2dl is affected by the flow of the molten resin when the fiber bundles2ul and 2dl move to downstream side with passing through both theinterstices (Hu and Hd) formed between the fixed opening pins 4ul and4ml and between the fixed opening pins 4ml and 4dl.

In other words, as shown in FIG. 7, the fixed opening pins 4ul, 4ml and4dl which upwardly or downwardly sandwich the continuous fiber bundles2ul and 2dl moving along a horizontal direction while keeping anapproximately horizontal posture may, for instance, be designed so as tocome close to the fiber bundles 2ul and 2dl from the positions slightlyshifted to the upstream and downstream directions respectively. Morespecifically, the fixed opening pins may likewise be arranged in such amanner that the fixed opening pin 4ul comes close to the fiber bundle2ul from the slightly upstream side, while the fixed opening pin 4mlcomes close to the fiber bundle 2ul from the slightly downstream sideand the fixed opening pin 4ml comes close to the fiber bundle 2dl fromthe slightly downstream side, while the fixed opening pin 4dl comesclose to the fiber bundle 2dl from the slightly upstream side. In thepresent invention, such an embodiment for sandwiching the fiber bundle 2will also be referred to as "multiple oblique sandwiching" below.

Thus, when arranging a plurality of fixed opening pins so that theyobliquely sandwich the continuous fiber bundles in this way, the twofixed opening pins 4u which are adjacent to one another along thevertical direction, as shown in FIG. 7, are arranged in such a mannerthat the plane perpendicular to that on which the fiber bundle 2 movesintersects the plane including both the central axes of these fixedopening pins at an angle "α" which satisfies the following relation:usually -45°≦α≦+45° and preferably -35°≦α≦+35°.

Therefore, as an embodiment wherein the fixed opening pin is arranged soas to realize such multiple oblique sandwiching of the continuous fiberbundle, the lower fixed opening pin may be positioned at the positioncontrast to that of the embodiment shown in FIG. 7. Incidentally, theforegoing has been described on the basis of the mounting positions ofthe fixed opening pins represented by the reference numerals 4ul, 4mland 4dl. In case where the continuous fiber bundle is subjected to themultiple oblique sandwiching, other fixed opening pins are also arrangedin the same manner described above.

Incidentally, in FIGS. 5 to 7, all the members which are identical tothose depicted on FIG. 4 bear the same reference numerals.

The columnar products can be produced by, preferably after cooling thecontinuous fiber-reinforced resin structure taken off through theshape-determining nozzle positioned on the downstream side of theforegoing opening and resin-impregnation apparatus or the multipleopening and resin-impregnation apparatus, cutting the resin-impregnatedstructure into pieces having a desired length using a means for cuttingthe structure (not shown) arranged in the vicinity of theshape-determining nozzle. The columnar product in general has an averagelength ranging from 3 to 50 mm, preferably 5 to 25 mm. The columnarproduct having such a length may be suitable for most applications. Thecutting means is not restricted to the foregoing specific one. Usually,the continuous fiber-reinforced resin structure taken off from theopening and resin-impregnation apparatus is cooled with water and thencut into pieces using a strand cutter to give the columnar products.

Continuous Fiber-Reinforced Resin Structure:

The continuous fiber impregnated with a molten resin within the openingand resin-impregnation apparatus can be taken off from the apparatusthrough an appropriately selected shape-determining nozzle and, ifnecessary, runs through another shape-determining nozzle or ashape-determining rolls to thus impart a variety of shapes to thecontinuous fiber-reinforced resin structure.

The continuous fiber-reinforced resin structure may be, for instance, avariety of materials having various shapes such as rod-like shapes(which may sometimes be referred to as strand or rod), e.g., rods havingcircular or square cross sections; tape-like bodies; sheet-like bodies;plate materials; and other various shaped sections. These continuousfiber-reinforced resin structures may be used as such or used in avariety of applications after forming into a desired shape by reheating.Moreover, the columnar products obtained by cutting a rod having acircular section and a diameter of about 1 to 3 mm can be used as amaterial for injection molding or extrusion molding.

Effects of the Invention

When the continuous fiber-reinforced resin structure (the structure is,for instance, a "sheet" and a "rod") of the invention is made by usingthe opening and rein-impregnation apparatus according to the presentinvention, various kinds of effects as listed below can be obtained.

(1) The fibers are not impaired (damaged) at all even when the take-offspeed of the continuous fiber-reinforced resin structure is increased to20 to 30 m/min. Therefore, the present invention permits continuousstable production of the resin structure over a long period of timewithout being accompanied by any fluffing.

(2) Surprisingly, an excellent ability of impregnation can be achievedalthough the continuous fiber (bundle) does not come in contact with thefixed opening pin. Accordingly, the foregoing continuousfiber-reinforced resin structure shows excellent mechanical strength.

(3) In addition, the fixed opening pins are substantially free from anydamage and wear due to the opening of the continuous fiber bundle.

(4) When continuous fiber rovings are used, the present inventionpermits easy continuous production of resin structures over a longperiod of time, the production of which cannot be attained by the use ofa single roving. This is because, the present invention permits completeelimination of the possibility of detachment of the the entangledrovings at the joined portions and the apparatus can continuously beoperated while adding rovings one after another.

(5) Moreover, if adopting the method which makes use of the multipleopening and resin-impregnation apparatus of the present invention, aplurality of continuous fiber bundle can simultaneously be processedwithout causing any problem due to the interference between rovings andthus the continuous fiber-reinforced resin structure can be produced inhigh efficiency.

(6) Moreover, if the continuous fiber-reinforced resin structure thusproduced is cut into pieces having a desired length, columnar productsin which continuous fibers having a length approximately identical tothat of the columnar products are unidirectionally arranged therein.

(7) The opening and resin-impregnation apparatus and the multipleopening and resin-impregnation apparatus according to the presentinvention have very high usefulness in the production of the continuousfiber-reinforced resin structure and the columnar products such as thosedescribed above.

EXAMPLES

The present invention will hereinafter be described while illustrating,by way of example, the production of a unidirectionally reinforced resinstructure which is reinforced with continuous fibers using the openingand resin-impregnation apparatus (1) of the present invention.

(1) Resin Impregnating Ability

The resulting unidirectionally reinforced resin structure in the form ofa strand, rod or the like is cut into pieces having a length of about100 mm, followed by immersing one end (10 mm) thereof in a solution ofMethyl Red in propanol (a solution obtained by adding 1 ml ofhydrochloric acid to 50 ml of a saturated propanol solution of MethylRed as a color-developing indicator to adjust the pH of the solution andto thus improve the color developing ability thereof) for 30 minutes,determining the raised liquid surface level of the color-developingindicator solution. Thus, the sample having a low level of the liquidsurface is defined as excellent in the resin-impregnation ability. Eachvalue determined is an arithmetic mean of 10 independent measurementsobserved for 10 samples. The details of the evaluation will be listed inTable 1.

The evaluation criteria for the determination and evaluation listed inthe following Tables 1 and 2 are as follows:

    ______________________________________                                                                Evaluation                                            ______________________________________                                        (1.1)                                                                              Height of Liquid Surface (mm)                                                                          Evaluation                                           less than 20             Excellent                                            not less than 20 and less than 40                                                                      Good                                                 not less than 40 and less than 60                                                                      Not Good                                             not less than 60 and less than 80                                                                      Bad                                                  not less than 80         Unacceptable                                    (1.2)                                                                              Flexural Strength (MPa)  According to                                                                  JIS K-7203                                      (1.3)                                                                              Stable Productivity                                                           (This is evaluated on the basis of the number                                 of occurrence of fluffing after passing                                       through a shape-determining nozzle)                                           not observed             Excellent                                            not less than 1 and less than 5                                                                        Good                                                 not less than 5 and less than 10                                                                       Not Good                                             not less than 11         Bad                                                  occurrence of interruption                                                                             Unacceptable                                    (1.4)                                                                              Views Concerning Passage of Connected Portion                                 (in particular, the behavior of the connected                                 portions upon passage through the interstice                                  between fixed opening pins)                                                   Passage Without Any Trouble                                                                            Favorable                                                                     Condition                                            Interruption due to Detachment                                                                         Detachment                                      ______________________________________                                         (The term "connected portion" used herein means the entangled end portion     of glass fiber rovings in which at least two fibers are added to one          another).                                                                

Example 1

Five glass fiber rovings (2) averaged single fiber diameter: 17 μm; tex:2310 g/km; number of bundling: 4000! were arranged in parallel relation,were fed to the opening and resin-impregnation apparatus (1) shown inFIG. 1 through a slit-like fiber-supply opening (3), ran through theapparatus and were continuously taken off at the downstream side. At thesame time, a melt of a modified polypropylene melting point of crystal(Tm; as determined by DSC method): 160° C.; MFR (21.2N; 230° C.): 130g/10 min; modified with maleic anhydride! was introduced into theapparatus (1) through an extruder (not shown) and the filamentatedcontinuous fibers (2F) were sufficiently impregnated with the moltenresin.

In each of three pairs of fixed opening pins (41u and 41d), (42u and42d) and (43u and 43d), all of the definition distances (clearance)(H41, H42 and H43) between the upper and lower fixed opening pins (4u)and (4d) were set at 1 mm (=60D). The temperature in the opening andresin-impregnation apparatus (1) was adjusted to 270° C. and aresin-impregnated structure (7) which was unidirectionally reinforcedwith glass continuous fibers was taken off at a velocity of 30 m/min inthe form of a rod.

The apparatus was operated at a rate of about 2.5 hours per roll of theroving over about 10 hours, while the final portion of the glass fiberroving (2) is connected, through entangling, to initial part of thesubsequent roving at the stage immediately before the completeconsumption of one roll thereof. As a result, it was observed that anyfluffing of the roving was not generated at all during the operation andthe connected portions between the rovings favorably passed through theapparatus The glass fiber roving (2) introduced into the opening andresin-impregnation apparatus (1) was taken off through theshape-determining nozzle (6: inner diameter 4 mm) which was an outletpositioned on the downstream end wall (1wR) of the apparatus (1), in theform of a continuous fiber-reinforced resin rod (7) which was shapedinto an approximately circular cross section.

The glass fiber content of the rod (7) was found to be 61% by weight,the resin-impregnation ability was judged to be "excellent" and the rodhad a flexural strength of 398 MPa. The stable productivity thereof wasevaluated to be "excellent" and the views concerning the passage of theconnected portion was also judged to be "favorable condition". Theseresults are summarized in the following Table 1.

Example 2

A continuous fiber-reinforced resin rod (7) was prepared according tothe same procedures and conditions used in Example 1 except that anapparatus shown in FIG. 2 as the opening and resin-impregnationapparatus (11) was used and various properties thereof determined wereevaluated. The foregoing apparatus (11) was operated as follows: A glasscontinuous fiber roving (2) was introduced into the apparatus (11) fromthe upper upstream side, followed by allowing the roving to run aroundthe turning pin (8) positioned at the most upstream side of theapparatus (11) to thus direct the roving to approximately horizontaldirection. Then, the roving passed through three pairs of fixed openingpins (41u and 41d; 42u and 42d; 43u and 43d) without coming in contactwith these pins to subject the roving to opening and impregnation, andwas taken off as a continuous fiber-reinforced resin rod (7) through ashape-determining nozzle (6)(inner diameter 4 mm) positioned at theoutlet of the apparatus (1). In this Example, all of the definitiondistances (H41, H42 and H43) between the upper fixed opening pin (4u)and the lower fixed opening pin (4d) which made a pair were set at alevel of 1 mm (=60D).

The glass fiber content of the resulting rod (7) was found to be 61% byweight, the resin-impregnation ability thereof was judged to be"excellent" and the rod had a flexural strength of 404 MPa. The stableproductivity thereof was evaluated to be "excellent" and the viewsconcerning the passage of the connected portion of the roving (7) wasalso judged to be "favorable condition". These results are summarized inTable 1.

There was not observed any fluffing of the glass fiber roving (2) duringthe operation of the apparatus and the connected portion of the roving(2) identical to that used in Example 1 could pass, without any troubleeven within the regions in and around the fixed opening pins (4) and theshape-determining nozzle (6).

Example 3

An apparatus used in this Example was that shown in FIG. 3 as theopening and resin-impregnation apparatus (12). The apparatus (12) shownin FIG. 3 was similar to the opening and resin-impregnation apparatus(1) shown in FIG. 1, provided that three upper fixed opening pins (41u,42u and 43u) of the three pairs of the fixed opening pins (41u and 41d;42u and 42d; 43u and 43d) were parallelly shifted towards the glassfiber roving (2)-supply side (upstream side) so that a straight line(sometimes referred to as "straight line u-d") connecting the centralaxes of the both upper and lower fixed opening pins (41u) and (41d),which made a pair, intersects the normal of the glass fiber roving (2)at an angle (intersectional angle) of 30° (towards left hand side)(inclined towards the upstream side), while the intersectional anglesfor the other paired pins, i.e., 42u and 42d as well as 43u and 43d werealso set at 30° (towards left hand side) and further the definitiondistances (H41, H42 and H43) between the upper and lower fixed openingpins (4u) and (4d) which made every corresponding pairs each was set at1 mm (=60D).

A continuous fiber-reinforced resin rod (7) was prepared according tothe same procedures and conditions used in Example 1 except that theopening and resin-impregnation apparatus (12) as shown in FIG. 3 wasused and various properties thereof determined were evaluated.

The glass fiber content of the resulting rod (7) was found to be 61% byweight, the stable productivity and the resin-impregnation abilitythereof were both judged to be "excellent" and the rod had a flexuralstrength of 392 MPa. The views concerning the passage of the connectedportion of the roving (7) was also judged to be "favorable condition".These results are summarized in Table 1.

There was not observed any fluffing of the glass fiber roving (2) duringthe operation of the apparatus even within the regions in and around thefixed opening pins (4) and the shape-determining nozzle (6).

Example 4

In the opening and resin-impregnation apparatus (13) used in thisExample, all of the definition distances (H41, H42 and H43) between theupper and lower fixed opening pins (4u) and (4d) which made everycorresponding pairs, i.e., the three pairs of the fixed opening pins(41u and 41d; 42u and 42d; 43u and 43d) fitted to the opening andresin-impregnation apparatus (1) as shown in FIG. 1 were set at a valueof 0.43 mm (=25D). A continuous fiber-reinforced resin rod (7) wasprepared according to the same procedures and conditions used in Example1 except that the opening and resin-impregnation apparatus (13) was usedand various properties thereof determined were evaluated.

The glass fiber content of the resulting rod (7) was found to be 61% byweight, the stable productivity and resin-impregnation ability thereofwere both judged to be "excellent" and the rod had a flexural strengthof 410 MPa. The view concerning the passage of the connected portion ofthe roving (7) was also judged to be "favorable condition". Theseresults are summarized in Table 1.

There was not observed any fluffing of the glass fiber roving (2) duringthe operation of the foregoing apparatus (13) even within the region inand around the fixed opening pins (4) and the shape-determining nozzle(6).

Example 5

A continuous fiber-reinforced resin rod (7) was prepared according tothe same procedures and conditions used in Example 1 except that, in theopening and resin-impregnation apparatus (14) used in this Example, allof the definition distances (H41, H42 and H43) between the upper andlower fixed opening pins (4u) and (4d) which made every correspondingpairs, i.e., the three pairs of the fixed opening pins (41u and 41d; 42uand 42d; 43u and 43d) fitted to the opening and resin-impregnationapparatus (1) as shown in FIG. 1 were set at a value of 43 mm (=250D).

The glass fiber content of the resulting rod (7) was found to be 61% byweight, the stable productivity and resin-impregnation ability thereofwere both judged to be "excellent" and the rod had a flexural strengthof 388 MPa. The view concerning the passage of the connected portion ofthe roving (7) was also judged to be "favorable condition". Theseresults are summarized in Table 1.

There was not observed any fluffing of the glass fiber roving (2) duringthe operation of the foregoing apparatus (14) even within the region inand around the fixed opening pins (4) and the shape-determining nozzle(6).

Example 6

A continuous fiber-reinforced resin rod (7) was produced using the sameprocedures and conditions described in Example 1 except that, in theopening and resin-impregnation apparatus (15) used in this Example, allof the definition distances (H41, H42 and H43) between the upper andlower fixed opening pins (4u) and (4d) in the three pairs of fixedopening pins (41u and 41d; 42u and 42d; 43u and 43d) fitted to theopening and resin-impregnation apparatus (1) shown in FIG. 1 wereadjusted to 6.8 mm (=400D) and that the take-off speed was raised up to35 m/min.

The glass content of the rod (7) was found to be 61% by weight, thestable productivity thereof was judged to be "excellent", theresin-impregnation ability thereof was judged to be "good" and theflexural strength thereof was found to be 379 MPa. The view concerningthe passage of the connected portion thereof was judged as "favorablecondition". These results obtained are listed in the following Table 1.

There was not observed any fluffing of the roving (2) during theoperation of the foregoing apparatus (15) even within the region in andaround the fixed opening pins (4) and the shape-determining nozzle (6).

Example 7

A continuous fiber-reinforced resin rod (7) was prepared according tothe same procedures and conditions used in Example 1 using the openingand resin-impregnation apparatus (1) shown in FIG. 1, except that thetemperature in the apparatus (1) was changed to 240° C. and that all ofthe definition distances (H4) between the fixed opening pins which madeevery corresponding pairs (4ud) were respectively set at 1.7 mm (=100D).The various properties of the rod (7) were determined and evaluated.

The glass fiber content of the resulting rod (7) was found to be 61% byweight, the resin-impregnation ability and stable productivity thereofwere both judged to be "excellent" and the rod had a flexural strengthof 390 MPa. The view concerning the passage of the connected portion ofthe roving (7) was also judged as "favorable condition". These resultsare summarized in Table 1.

Example 8

A continuous fiber-reinforced resin rod (7) was prepared according tothe same procedures and conditions used in Example 1 using the openingand resin-impregnation apparatus (1) shown in FIG. 1, except for using,as the thermoplastic resin, 6,6-polyamide resin relative viscosity: 2.50(using a 98% sulfuric acid solution as defined in JIS K6810); tradename: Nylon 2015B; available from Ube Industries, Ltd.!.

The glass fiber content of the resulting rod (7) was found to be 56% byweight, the resin-impregnation ability was judged to be "excellent" andthe stable productivity thereof was judged to be "good" and the rod hada flexural strength of 477 MPa. The view concerning the passage of theconnected portion of the roving (7) was also judged as "favorablecondition". These results are summarized in Table 1.

Example 9

The same procedures used in Example 1 were repeated according to thesame rocedures and conditions used in Example 1 using the opening andresin-impregnation apparatus (1) shown in FIG. 1, except that a maleicanhydride-modified polypropylene (MAH-PP) MFR (21.2N; 230° C.) 130 g/10min! as the thermoplastic resin was supplied to the apparatus (1) in itsmolten state, that there was used a continuous fiber bundle-introducingopening (3) which permitted the simultaneous introduction of 5 glassfiber rovings (2) arranged in parallel to thus introduce 5 continuousfiber bundles (2) arranged in parallel, that 5 nozzles having a circularcross section (inner diameter 2.4 mm) were arranged in an almostparallel relation, that all of the definition distances (H41, H42, H43and H44) between the fixed opening pins which made four pairs of fixedopening pins (4ud) were adjusted to 1.4 mm (=85D) and that thetemperature was changed to 260° C.

All of the glass fiber contents of the resulting 5 continuousfiber-reinforced resin strands (7) were found to be 40% by weight, theresin-impregnation ability and the stable productivity thereof were bothjudged to be "excellent" and the view concerning the passage of theconnected portion was judged as "favorable condition". The reinforcedstrand (7) was cut (or pelletized) into pieces having a length of 10 mmand then used in injection-molding to give a test piece. The test piece(4 mm thick×10 mm long×100 mm wide) was found to have a flexuralstrength of 201 MPa. These results are summarized in Table 1.

Example 10

A structure (7) reinforced with substantially unidirectionally arrangedsheet-like glass continuous fibers was prepared according to the sameprocedures and conditions used in Example 1, except that the dimensionof the rectangular nozzle for shaping was changed to 0.24 mm long×60 mmwide.

The stable productivity thereof was judged to be "excellent" since therewas not observed any fluffing throughout the operation of the openingand rein-impregnation apparatus (1). Moreover, the connected portionbetween the end portion of the preceeding glass roving (7) and theinitial portion of the subsequent glass roving (7) satisfactorily passedthrough the foregoing apparatus (1). The glass content of the resultingreinforced sheet was found to be 60% by weight. The reinforced sheet (7)was cut along the direction of the reinforcing fiber included therein atan arbitrary position to give a strip (100 mm long×10 mm wide), then theresin-impregnation ability thereof was determined by repeating the sameprocedures used in Example 1 and it was judged to be "excellent".

Similarly, the reinforced sheet (7) was cut along the direction of thereinforcing fiber included therein at another arbitrary position to givea strip (10 mm long×10 mm wide).

Twelve of these sheets were put in layers while arranging thereinforcing fibers included therein in one direction, followed bypressing with heating at a temperature of 200° C. and a pressure of 0.2MPa to give a reinforced laminate. The flexural strength of the laminatewas determined using it as a specimen (100 mm long×10 mm width×2.8 mmthick) and was found to be 608 MPa.

Comparative Example 1

The same procedures used in Example 1 were repeated under the sameconditions described in Example 1 to try to prepare a continuousfiber-reinforced resin rod (7) and to determine the properties thereofand evaluate the results thus determined, except for using an apparatushaving the following construction such as the opening andresin-impregnation apparatus (16) shown in FIG. 4 and that a glass fiberroving (2) ran in such a manner that it ran around the peripheral faceof each fixed opening pin (4) in a zigzag pattern. As a result, it wasfound that fluffing was frequently observed at take-off speed of areinforced rod (7) of 20 m/min and that the operation of the opening andresin-impregnation apparatus (16) became impracticable.

Incidentally, the circle depicted at the upper portion of the fixedopening pin (4) by a broken line in FIG. 4 indicates that the openingand resin-impregnation apparatus (16) of the present invention may beprovided with the upper fixed opening pins (4u) arranged at desiredspaces, at such positions. These results are summarized in Table 1.

Comparative Example 2

There was assembled a test apparatus (17) by removing all of the fixedopening pins (4) from the opening and resin-impregnation apparatus (11)as shown in FIG. 2, except for the turning pins (8) positioned at themost upstream side (or these pins may be transferred to positionslocating far away from the glass fiber roving).

A continuous fiber-reinforced resin rod (7) was prepared according tothe same procedures and conditions described in Example 2, except forusing the test apparatus (17) shown in FIG. 4. There was not observedany fluffing of the glass fiber roving (2) during the operation of theapparatus (17), the connected portions of the roving (2) satisfactorilypassed through the apparatus to thus give a continuous fiber-reinforcedresin rod (7).

However, the resin-impregnation ability of the rod (7) was judged to be"bad" and the flexural strength thereof was found to be unsatisfiedlevel on the order of 231 MPa, while only the stable productivity wasjudged to be "good". These results are summarized in Table 1.

Comparative Example 3

A continuous fiber-reinforced resin rod (7) was produced according tothe same procedures and conditions used in Example 1, using a openingand resin-impregnation apparatus (18) which was mechanically similar tothe apparatus (1) used in Example 1 except for setting the definitiondistances (H41, H42 and H43) between the upper and lower fixed openingpins (4u) and (4d), which made a pair, for the three paired fixedopening pins (41u and 41d; 42u and 42d; 43u and 43d) which were fittedto the apparatus (1) shown in FIG. 1 at a level of 0.1 mm (=6D). Theresin-impregnation ability of this rod (7) was evaluated to be"excellent" and the flexural strength thereof was found to be 385 MPa,but the operation of the apparatus was insufficient since the stableproductivity thereof was judged to be "bad" as will be detailed below.These results are summarized in Table 1.

When operating the foregoing apparatus (18), the glass fiber roving (2)introduced into the apparatus came in contact with at least one fixedopening pin (4) and there was observed severe fluffing of the roving(2). This would be ascribed to the fact that the foregoing minimumdistance (H) is too small. Moreover, the connected portions of theroving (2) were disconnected from one another within the apparatus (18)and accordingly, there was observed such an accident that the rovingshould be replaced while temporarily stopping the apparatus.

Comparative Example 4

A continuous fiber-reinforced resin rod (7) was produced according tothe same procedures and conditions used in Example 1, using a openingand resin-impregnation apparatus (19) which was mechanically similar tothe apparatus (1) used in Example 1 except for setting the definitiondistances (H41, H42 and H43) between the upper and lower fixed openingpins (4u) and (4d), which made a pair, for the three paired fixedopening pins (41u and 41d; 42u and 42d; 43u and 43d) which were fittedto the apparatus (1) shown in FIG. 1 at a level of 10.2 mm (=600D).

The resin-impregnation ability of this rod (7) was evaluated to be "bad"and the flexural strength thereof was found to be 243 MPa, but only thestable productivity thereof was judged to be "excellent". These resultsare summarized in Table 1.

Comparative Example 5

A test apparatus (20) was assembled by removing the three upper fixedopening pins (41u, 42u and 43u) from the opening and resin-impregnationapparatus (1) as shown in FIG. 1. Then a continuous fiber-reinforcedresin rod (7) was produced according to the same procedures andconditions used in Example 1, except that the opening andresin-impregnation apparatus (20) as shown in FIG. 4 was used and theproduction method was so designed that the glass roving (2) passed abovethe remaining fixed opening pins (41d, 42d and 43d).

The resulting rod (7) had a glass content of 61% by weight, theresin-impregnation ability thereof was judged to be "bad" and theflexural strength thereof was found to be 260 MPa, but the stableproductivity was judged as "excellent". These results are summarized inTable 1.

In the operation using the foregoing test apparatus (20), there was notobserved any fluffing of the roving (2) even when the take-off speed ofthe rod was set at a level of 30 m/min and the connected portions of therovings satisfactorily passed through the apparatus (4) and theprescribed operation of the apparatus was completed.

                                      TABLE 1                                     __________________________________________________________________________    C.                                                                            Opening and resin-impregnation apparatus                                                     Opening pin                                                    Roving                   Angle of                                                                             Polymer material                                   Introduction and                                                                             H/D  inclination MFR                                      Ex. No                                                                             running directions                                                                      Pair (ratio)                                                                            (α°)                                                                    Kind g/10 min                                 __________________________________________________________________________    Ex. 1                                                                              Horizontal                                                                          Straight                                                                          3     60  0      MAH-PP                                                                             130                                      Ex. 2                                                                              Off upper                                                                           Straight                                                                          3     60  0      MAH-PP                                                                             130                                      Ex. 3                                                                              Horizontal                                                                          Straight                                                                          3     60  left 30                                                                              MAH-PP                                                                             130                                      Ex. 4                                                                              Horizontal                                                                          Straight                                                                          3     30  0      MAH-PP                                                                             130                                      Ex. 5                                                                              Horizontal                                                                          Straight                                                                          3    250  0      MAH-PP                                                                             130                                      Ex. 6                                                                              Horizontal                                                                          Straight                                                                          3    460  0      MAH-PP                                                                             130                                      Ex. 7                                                                              Horizontal                                                                          Straight                                                                          3    100  0      MAH-PP                                                                             130                                      Ex. 8                                                                              Horizontal                                                                          Straight                                                                          3     60  0      6,6-NL                                                                             --                                       Ex. 9                                                                              Horizontal                                                                          Straight                                                                          4     85  0      MAH-PP                                                                             130                                      Ex. 10                                                                             Horizontal                                                                          Straight                                                                          3     60  0      MAH-PP                                                                             130                                      Comp.                                                                              Horizontal                                                                          Zigzag                                                                            None Outside                                                                            Outside                                                                              MAH-PP                                                                             130                                      Ex. 1               Subject                                                                            Subject                                              Comp.                                                                              Off upper                                                                           Straight                                                                          None Outside                                                                            Outside                                                                              MAH-PP                                                                             130                                      Ex. 2               Subject                                                                            Subject                                              Comp.                                                                              Horizontal                                                                          Straight                                                                          3     6   0      MAH-PP                                                                             130                                      Ex. 3                                                                         Comp.                                                                              Horizontal                                                                          Zigzag                                                                            3    600  0      MAH-PP                                                                             130                                      Ex. 4                                                                         Comp.                                                                              Horizontal                                                                          Zigzag                                                                            None Free of                                                                            Outside                                                                              MAH-PP                                                                             130                                      Ex. 5               upper pin                                                                          Subject                                              __________________________________________________________________________    C.                                                                            Conditions                  Continuous fiber-reinforced                       for operation  Operation state                                                                            resin structure                                       Opening and                                                                              Views of     Glass                                                 impregnation                                                                        Take-off                                                                           passage of   fiber                                                                             Resin  Flexural                                   temperature                                                                         speed                                                                              connected                                                                           Stable content                                                                           impregnation                                                                         Strength                               Ex. No                                                                            (° C.)                                                                       m/min                                                                              portions                                                                            productivity                                                                         (wt %)                                                                            ability                                                                              MPa                                    __________________________________________________________________________    Ex. 1                                                                             270   30   Satisfactory                                                                        Excellent                                                                            61  Excellent                                                                            398                                    Ex. 2                                                                             270   30   Satisfactory                                                                        Good   61  Excellent                                                                            404                                    Ex. 3                                                                             270   30   Satisfactory                                                                        Excellent                                                                            61  Excellent                                                                            392                                    Ex. 4                                                                             270   30   Satisfactory                                                                        Excellent                                                                            61  Excellent                                                                            410                                    Ex. 5                                                                             270   30   Satisfactory                                                                        Excellent                                                                            61  Excellent                                                                            388                                    Ex. 6                                                                             270   35   Satisfactory                                                                        Excellent                                                                            61  Good   379                                    Ex. 7                                                                             240   30   Satisfactory                                                                        Excellent                                                                            61  Excellent                                                                            390                                    Ex. 8                                                                             300   30   Satisfactory                                                                        Good   56  Excellent                                                                            477                                    Ex. 9                                                                             260   30   Satisfactory                                                                        Excellent                                                                            40  Excellent                                                                             201*                                  Ex. 10                                                                            270   30   Satisfactory                                                                        Excellent                                                                            60  Excellent                                                                             608**                                 Comp.                                                                             270   <30  --    Unacceptable                                                                         --  --     --                                     Ex. 1                                                                         Comp                                                                              270   30   Satisfactory                                                                        Good   62  Unacceptable                                                                         231                                    Ex. 2                                                                         Comp.                                                                             270   30   Detaching                                                                           Slightly bad                                                                         61  Bad    385                                    Ex. 3                                                                         Comp.                                                                             270   30   Satisfactory                                                                        Bad    61  Slightly bad                                                                         253                                    Ex. 4                                                                         Comp.                                                                             270   30   Satisfactory                                                                        Bad    61  Slightly bad                                                                         260                                    Ex. 5                                                                         __________________________________________________________________________     H: The distance between the opening pins which make a pair;                   D: Average diameter of single fibers consitituting glass fiber roving (in     the present case 17 mm);                                                      MAHPP: Maleic anhydridemodified PP;                                           6,6NL: 6,6nylon (6,6polyamide resin)                                          Connected portion: a portion in which glass fiber rovings were connected      with each other                                                               Detaching: Detaching of the connected portion of the glass fiber rovings      *: A value determined using test pieces (specimens), the stable               productivity, resinimpregnation ability, flexural strength and views          concerning the passage of the connected portions were determined and/or       evaluated according to the description disclosed in this specification;       **: A measured value for laminated products.                             

Example 11

FIG. 4 is a schematic longitudinal sectional view of a multiple openingand resin-impregnation apparatus. There was used, as themultiple openingand resin-impregnation apparatus (1; a opening and resin-impregnationdie), a multiple opening and resin-impregnation apparatus (1) having awidth (length in the direction perpendicular to the longitudinaldirection) of 200 mm and comprising a vessel having a box-like shape(whose cross section is a rectangular shape as shown in FIG. 4); threesets of fixed opening pins (4) arranged towards the downstream directionin which pins in each set are installed between the side walls (wallsextending along the longitudinal direction; not shown) constituting thevessel and vertically arranged in 3 stages; and upper roving-supplynozzle (3u) and lower roving-supply nozzle (3d) arranged on the upstreamend wall (1wL) in two stages. Twelve glass fiber rovings (4) weredivided into two groups, one group thereof comprising 6 rovingshorizontally arranged was introduced into the multiple opening andresin-impregnation apparatus (1) through the upper roving-supply nozzle(u), while the other group comprising 6 rovings likewise horizontallyarranged was introduced into the apparatus through the lowerroving-supply nozzle (d).

In the following description, the present invention will be explainedwhile taking, as an example, an apparatus which comprises upper andlower, 2-stage, rovings (2ul and 2dl); upper and lower, 2-stage,roving-supply nozzles (3u and 3d); upper and lower, 2-stage, reinforcingstrands (7u and 7d); and upper and lower, 2-stage, shape-determiningnozzles (6ul and 6dl) formed on the downstream end wall (1wR) of theapparatus (1). More specifically, in the deeper part of the apparatusshown in FIG. 4, there are additionally present 5 series of upper andlower, 2-stage, rovings (2u2 to 2u6 and 2d2 to 2d5); upper and lower,2-stage, roving-supply nozzles (3u2 to 3u6 and 3d2 to 3d6); upper andlower, 2-stage, reinforcing strands (7u2 to 7u6 and 7d2 to 7d6); andupper and lower, 2-stage, shape-determining nozzles (6u2 to 6u6 and 6d2to 6d6) formed on the downstream end wall (1wR) of the apparatus (1).

However, only the forefront series thereof as shown in each figure willhereinafter be described in the present invention. This is because thesituation is also true of the other 5 series and accordingly, theexplanation of the latter will be omitted for preventing the redundancyof the explanation.

More particularly, the foregoing arrangement is as follows:

Roving-Introducing Nozzle!: Among the upper roving-introducing nozzles(abbreviation: "upper nozzle"), shown in FIG. 4 is the upper nozzle(3ul) while the lower nozzle (3dl) is shown in this figure.

Fixed Opening Pins!: The fixed opening pins (4) arranged in theforegoing pattern were composed of upper-stage fixed opening pins (4ul,4u2 and 4u3); middle-stage fixed opening pins (4ml, 4m2 and 4m3); andlower-stage fixed opening pins (4dl, 4d2 and 4d3).

Roving!: The foregoing glass continuous fiber roving (2) is roughlydivided into two groups, i.e., upper-stage rovings (2u) and lower-stagerovings (2d) and those shown in FIG. 4 are the upper-stage roving (2u1)and the lower-stage roving (2d1).

To the apparatus (1), there was fed a molten thermoplastic resin formedin a melting and kneading device (not shown) such as an extruder througha molten resin-introduction opening (5) formed on the bottom plate (1wb)of the apparatus (1). The upper-stage roving (2ul) positioned in theupper-stage among the twelve rovings (2) introduced into the apparatuswas passed through the space between the upper-stage fixed opening pin(4u1) and the middle-stage fixed opening pin (4m1) without coming incontact with both of these pins, while the lower-stage roving (2dl)positioned in the lower-stage was passed through the space between themiddle-stage fixed opening pin (4m1) and the lower-stage fixed openingpin (4d1) without coming in contact with both of these pins.

Then, the filamentated products (2u1 and 2d1) thus formed wereimpregnated with the molten resin to give composites (7; also referredto as "reinforced strand") comprising the continuous fibers (2) and theresin and the upper reinforced strand (7u1) positioned in theupper-stage and the lower reinforced strand (7d1) positioned in thelower-stage were recovered through the upper-stage shape-determiningnozzle (6u1; inner diameter 2.4 mm) and the lower-stageshape-determining nozzle (6d1) positioned at the downstream end wall(1wR) of the multiple opening and resin-impregnation apparatus (1) usinga take-off device (not shown) to thus give two reinforced strands, i.e.,upper-stage and lower-stage reinforced strands (7u1) and (7d1).

In this regard, the apparatus is provided with one shape-determiningnozzle per roving and those shown in FIG. 4 (the forefront nozzles ofthe apparatus shown in FIG. 4) correspond to the upper-stage andlower-stage shape-determining nozzles (6u1) and (6d1).

There was not observed any fluffing throughout the operation of themultiple opening and resin-impregnation apparatus (1) and the connected(entangled) portions of the first and second rolls of rovings alsosatisfactorily passed through the apparatus (the stable productivitythereof was judged as "excellent").

These upper-stage and lower-stage reinforced strands (7ud) were cut intosmall pieces to give reinforced pellets (having an average length of 10mm).

The reinforced pellets (7) were used in injection molding to formspecimens. When determining and evaluating the resin-impregnationability of the reinforced strand (7) and the flexural strength of thespecimen thus formed, there were obtained good results in that theformer was judged to be "excellent" and the latter was found to be "215MPa". These results are summarized in Table 2.

In this connection, the thermoplastic resin supplied from the extruderwas a maleic anhydride-modified polypropylene MFR (230° C.; 21.2N) 130g/10 min!; the glass fiber roving (2) used was a product available fromNippon Electric Glass Co., Ltd. having an averaged single fiber diameter(D) of 17 μm and a tex of 2310 g/km; the space between the upper andlower fixed opening pins which make a pair (6 portions in all) was setat 1 mm (=60D); the multiple opening and resin-impregnation apparatus(1) was operated at a temperature of 270° C.; and the take-off speed ofthe resulting composite was adjusted to 30 m/min.

Example 12

The same procedures and conditions used in Example 11 were repeatedexcept for using the multiple opening and resin-impregnation apparatus(11) shown in FIG. 5 to obtain a reinforced strand (7), followed byfinely cutting the strand thus formed to give reinforced pellets (havingan average length of 10 mm). More specifically, twelve (6 rovings foreach stage) glass continuous fiber rovings (2u1 and 2d1) were introducedinto the multiple opening and resin-impregnation apparatus (11) throughthe continuous fiber-supply opening (3) positioned on the upstream sideof the top plate of the apparatus, followed by coming each roving incontact with the corresponding upstream turning pin (8u or 8d; there aretwo such pins positioned in the upper-and lower-stages within theapparatus) in such a manner that they ran around the lower side of eachpin to thus convert the moving direction into the horizontal direction.

Subsequently, the rovings were treated by the same procedures used inExample 11 to give two reinforced strands (7u1 and 7d1). Although therovings (2) always came in contact with the upstream turning pinsthroughout the operation of the apparatus, there was not observed anyfluffing during the operation of the apparatus (1), and the connected(entangled) portions of the first and second rolls of the rovings (2)could satisfactorily pass through the apparatus (the stable productivitythereof was judged to be "good").

The resulting two reinforced strands (7ul and 7d1) were inspected forthe resin-impregnation ability and finely cut into pieces to givereinforced pellets, followed by injection-molding the reinforced pelletsto give specimens (test pieces) and determination of the flexuralstrength thereof. As a result, good results were obtained, i.e., theformer was judged to be "excellent" and the latter was found to be "222MPa". These results are listed in the following Table 2.

Example 13

The multiple opening and resin-impregnation apparatus (12; also referredto as "opening and impregnation die") shown in FIG. 6 is such anaparatus that the apparatus (1) shown in FIG. 4 is further provided withupper and lower two downstream turning pins (9u1 and 9d1) verticallyarranged downstream of the downstream terminal fixed opening pins.

Using the multiple apparatus (12), 12 glass fiber rovings (2) weredivided into two upper and lower groups each comprising 6 rovings) andthe rovings belonging to each group were arranged horizontally, followedby introduction of these groups into the multiple opening andresin-impregnation apparatus (12) through two upper-stage andlower-stage roving-introduction openings (3u1) and (3d1) formed on theupstream end wall (12wL) of the apparatus (12).

Subsequently, a melt of a maleic anhydride-modified polypropylene resinMFR (230° C.; 21.2N) 130 g/10 min! prepared in a melting and kneadingdevice (not shown) was introduced into the multiple apparatus (12) tothus subject the rovings to opening and resin-impregnation in the samemanner in Example 11.

The space formed between upper and lower fixed opening pins (4ud), whichmade a pair (6 pairs in all), was set at 1 mm (=60D) for all of thesepairs. In the foregoing multiple apparatus (12), the spaces between theupper-stage (relative relationship concerning the positions of pins)fixed opening pin and the lower-stage (relative relationship concerningthe positions of pins) fixed opening pin (6 positions in all) were allset at a single value of 1 mm(=60D). This multiple apparatus (12) wasoperated at a temperature of 270° C. and a take-off speed of theresulting reinforced strand (71) of 30 m/min.

One roll of the foregoing glass continuous fiber roving (2) would beconsumed within about 4 hours and accordingly, a second roll of theroving (2) was provided.

More specifically, the end portion of the roving (2) during processingwas connected to the initial end of the second roving (2) throughentangling at an instance when the first roving came up to its terminalpoint to thus continue the operation of the apparatus.

There was not observed any fluffing throughout the operation of theapparatus in this Example 13 and the connected portions between thesuccessive two rovings could satisfactorily pass through the multipleapparatus (12) (i.e., the stable productivity thereof was judged to be"good").

The moving direction of these upper-stage and lower-stage continuousfiber composite materials (2u1 and 2d1) which had been subjected toopening and impregnation with the molten resin in the apparatus (12) waschanged by bringing them into contact with the surface of eachcorresponding upper or lower downstream turning pin (9u1 or 9d1)arranged between the final fixed opening pin and the shape-determiningnozzle (61; inner diameter 6.3 mm) downstream of the pin to thusconverge these composites on the same shape-determining nozzle (61).

The resulting single reinforced strand (71; reinforced rod) had a glasscontinuous fiber content of 60% by weight. This reinforced rod (71) wasinspected for the resin-impregnation ability and the flexural strengthwithout subjecting it to any treatment.

Thus, the reinforced rod was inspected or evaluated for theresin-impregnation ability and the flexural strength and as a result,good results were obtained, i.e., the former was judged as "excellent"and the latter was found to be "403 MPa". These results are listed inthe following Table 2.

Example 14

The multiple opening and resin-impregnation apparatus (13) used in thisExample was such an apparatus that, in the multiple apparatus (1) shownin FIG. 5, three fixed opening pins (4u1, 4u2 and 4u3) systematicallyarranged in the upper-stage and three fixed opening pins (4d1, 4d2 and4d3) systematically arranged in the lower-stage are horizontally shiftedtowards the downstream direction of the apparatus (1) and that all ofthe intersectional angles (α) formed between the line connecting thecenters of the upper-stage and lower-stage fixed opening pins (4u) and(4d) and a line perpendicular to the running direction of the continuousfiber (2) (3 portions in all) were set at +40° (the counterclockwisedirection is represented by "+" in the figure).

The same procedures and conditions used in Example 11 were repeatedexcept for using this multiple apparatus (13) to give two upper-stageand lower-stage reinforced strands (7u1 and 7d1), followed by finelycutting them to give reinforced pellets (7; having an average length of10 mm). The reinforced pellets (7) were subjected to injection-moldingin the same manner in Example 11 to give specimens.

The strand (7) was inspected for the resin-impregnation ability, theresulting specimen was inspected for the flexural strength and theseresults were evaluated. As a result, good results were obtained, i.e.,the former was judged to be "excellent" and the latter was found to be"200 MPa". These results are summarized in the following Table 2.

There was not observed any fluffing throughout the operation of themultiple opening and resin-impregnation apparatus (13) and the connectedportions of the glass continuous fiber rovings (2) could satisfactorilypass through the multiple apparatus (13) (i.e., the stable productivitywas evaluated as "excellent").

Example 15

The multiple opening and resin-impregnation apparatus (14) used in thisExample was such an apparatus that, in the multiple apparatus (1) asshown in FIG. 5, the space (clearance) between the upper-stage andlower-stage fixed opening pins or, for instance, the space (Hu1) betweenthe upper-stage and middle-stage fixed opening pins (4u1) and (4m1) orthe space (Hd1) between the middle-stage and lower-stage fixed openingpins (4m1) and (4d1) (6 portions in all) was set at a level of 0.5 mm(=30D).

The same procedures and conditions used in Example 11 were repeatedexcept for using this multiple apparatus (14) to give two upper-stageand lower-stage reinforced strands (7u1 and 7d1), followed by finelycutting them to give reinforced pellets (7; having an average length of10 mm). The reinforced pellets (7) were subjected to injection-moldingin the same manner as in Example 11 to give specimens.

The strand (7) was inspected for the resin-impregnation ability and theresulting specimen was inspected for the flexural strength and theseresults were evaluated. As a result, good results were obtained, i.e.,the former was judged to be "excellent" and the latter was found to be"224 MPa". These results are summarized in the following Table 2.

There was not observed any fluffing throughout the operation of themultiple opening and resin-impregnation apparatus (14) and the connectedportions of each of these two upper and lower-stage glass continuousfiber rovings (2u1 and 2d1) could satisfactorily pass through themultiple apparatus (14) (i.e., the stable productivity was evaluated as"excellent").

Example 16

The multiple opening and resin-impregnation apparatus (15) used in thisExample was such an apparatus that, in the multiple apparatus (1) asshown in FIG. 5, the space (H) between the upper-stage and lower-stagefixed opening pins, i.e. the space (Hu1) between the upper-stage andmiddle-stage fixed opening pins (4u1) and (4m1) or the space (Hd1)between the middle-stage and lower-stage fixed opening pins (4m1) and(4d1) (6 portions in all) was set at a level of 4.3 mm (=250D). The sameprocedures and conditions used in Example 11 were repeated except forusing this multiple apparatus (15) to give two, i.e., upper-stage andlower-stage reinforced strands (7u1 and 7d1), followed by finely cuttingthem to give reinforced pellets (having an average length of 10 mm).

The reinforced pellets (7) were subjected to injection-molding in thesame manner as in Example 11 to give specimens. The strand (7) wasinspected for the resin-impregnation ability, the resulting specimen wasinspected for the flexural strength and these results were evaluated. Asa result, good results were obtained, i.e., the former was judged to be"excellent" and the latter was found to be "210 MPa".

There was not observed any fluffing throughout the operation of themultiple opening and resin-impregnation apparatus (15) and the connectedportions of the glass continuous fiber rovings (2) could satisfactorilypass through the multiple apparatus (15), i.e., the stable productivitywas evaluated as "excellent". These results are summarized in thefollowing Table 2.

Example 17

The multiple opening and resin-impregnation apparatus (16) used in thisExample was such an apparatus that, in the multiple apparatus (1) asshown in FIG. 5, the space (Hu1 and Hd1) between the upper-stage andlower-stage fixed opening pins (6 portions in all) was set at a level of6.8 mm (=400D). The same procedures and conditions used in Example 11were repeated except for using this multiple apparatus (16) to give two,i.e., upper-stage and lower-stage reinforced strands (7u1 and 7d1),followed by finely cutting them to give reinforced pellets (having anaverage length of 10 mm).

The reinforced pellets (7) were subjected to injection-molding in thesame manner as in Example 11 to give specimens. The strand (7) wasinspected for the resin-impregnation ability and the resulting specimenwas inspected for the flexural strength and these results wereevaluated. As a result, good results were obtained, i.e., the former wasjudged to be "good" and the latter was found to be "197 MPa".

There was not observed any fluffing throughout the operation of themultiple opening and resin-impregnation apparatus (16) and the connectedportions of the glass continuous fiber rovings (2) could satisfactorilypass through the multiple apparatus (15), i.e., the stable productivitywas evaluated as "excellent". These results are summarized in thefollowing Table 2.

Comparative Example 6

It was tried to obtain upper-stage and lower-stage reinforced strands(7u1 and 7d1) according to the same procedures and conditions used inExample 11 except for using a multiple opening and resin-impregnationapparatus (17) as shown in FIG. 9 which was an approximately box-likeshape. More specifically, the multiple apparatus (17) has a width (thelength in the direction perpendicular to the running direction of thecontinuous fiber in a horizontal plane) of 200 mm and is provided withupper and lower, two-stage fixed opening pins (4u and 4d) which areinstalled between the right hand side wall (not shown) and the left handside wall (not shown) and are arranged within these two side walls in azigzag pattern. However, the stable productivity of the resulting strandwas judged to be "unacceptable" because of the following reasons.

Composite materials comprising the foregoing upper and lower, two-stagecontinuous fiber reinforcing materials (2u1 and 2d1) and a resin weretaken off through the upper and lower, two-stage shape-determiningnozzles (17u1 and 17d1), respectively, formed on the downstream end wall(17wR) of the multiple opening and resin-impregnation apparatus (17) tothus give reinforced strands (7u1 and 7d1). In this connection, thetake-off speed of the strands were set at 30 m/min. However, the tensionapplied to the continuous fiber rovings (2u1 and 2d1) became extremelyhigh and accordingly, fluffing of the rovings occurred frequently andthe apparatus could not be operated within a short period of time.

Therefore, the resin-impregnation ability and the flexural strengthcould not be determined. These results are summarized in the followingTable 2.

Comparative Example 7

Upper and lower, two-stage reinforced strands (7u1 and 7d1) wereproduced by repeating the same procedures and conditions used in Example12 with using a multiple opening and resin-impregnation apparatus (18)which was such an apparatus that, in the multiple apparatus (11), all ofthe fixed opening pins (4) were removed while remaining the two turningpins (8u1 and 8d1) on the upstream side as shown in FIG. 10, followed byfinely cutting the reinforced strands to give reinforced pellets (7).The resulting reinforced pellets (7) were used in injection-molding tothus produce test pieces by repeating the same procedures and conditionsused in Example 11. The resin-impregnation ability and the flexuralstrength thereof were determined and evaluated.

The fluffing was not so conspicuous during the production of thereinforced strand (7) and the connected portions of the rovings (2)could satisfactorily pass through the multiple apparatus, i.e., thestable productivity was judged to be "good". However, theresin-impregnation ability of the resulting reinforced strand (7) wasranked as "unacceptable" and the flexural strength thereof was found tobe "121 MPa" which did not reach the desired level. These results aresummarized in the following Table 2.

Comparative Example 8

A reinforced strand (71; forefront strand shown in the figure) wasproduced by repeating the same procedures and conditions used in Example12 with using a multiple opening and resin-impregnation apparatus (19)which was such an apparatus that in the multiple apparatus (12), all ofthe fixed opening pins (4) were removed while remaining the two turningpins (9u and 9d) on the downstream side as shown in FIG. 11. Theresin-impregnation ability and the flexural strength of the resultingreinforced rod (71) were determined and evaluated. The results thusobtained are summarized in the following Table 2.

The fluffing was not so conspicuous during the production of thereinforced strand (7) and the connected portions of the rovings (2)could satisfactorily pass through the multiple apparatus, i.e., thestable productivity was judged to be "good". However, theresin-impregnation ability of the resulting reinforced rod (7) was foundto be insufficient and the flexural strength thereof was found to be"251 MPa" which did not reach the desired level.

Comparative Example 9

Upper and lower, two-stage reinforced strands (7u1 and 7d1) wereproduced by repeating the same procedures and conditions used in Example11 with using a multiple opening and resin-impregnation apparatus (20)which was such an apparatus that, in the multiple apparatus (1) used inExample 10, the spaces (Hu1 and Hd1) between the upper-stage fixedopening pin and the lower-stage fixed opening pin which made a pair wereall set at 0.1 mm (=6D). The resulting reinforced strands were finelycut into reinforced pellets (7), followed by subjecting the reinforcedpellets (7) to injection-molding to thus produce specimens according tothe same procedures and conditions used in Example 11.

The resin-impregnation ability of the reinforced strands (7) and theflexural strength of the resulting specimen were determined andevaluated. Thus, good results were obtained, i.e., the former was judgedto be "excellent" and the latter was found to be "216 MPa", but thestable productivity thereof was ranked as "not good". The results thusobtained are summarized in the following Table 2.

The fluffing occurred frequently since the roving (2) frequently came incontact with the fixed opening pins (4) during the production of theforegoing reinforced strand (7). Moreover, the connected portions of therovings (2) caused detaching in the multiple apparatus and as a result,the operation of the multiple apparatus should be once stopped in orderto replace the rovings.

Comparative Example 10

Upper and lower, two-stage reinforced strands (7) were produced byrepeating the same procedures and conditions used in Example 10 withusing a multiple opening and resin-impregnation apparatus (21) which wassuch an apparatus that, in the multiple apparatus (1) used in Example11, the spaces (Hu1 and Hd1) between the upper-stage fixed opening pinand the lower-stage fixed opening pin which made a pair were all set at10.2 mm (=600D). The resulting reinforced strand was finely cut intoreinforced pellets (7), followed by subjecting the reinforced pellets(7) to injection-molding to thus produce specimens in the sameprocedures and conditions used in Example 11.

The resin-impregnation ability of the reinforced strands (7) and theflexural strength of the specimen prepared from the reinforced pellets(7) were determined and evaluated. Thus, the former was judged to be"not good" and the latter was found to be "138 MPa", but the stableproductivity thereof was ranked as "excellent". The results thusobtained are summarized in the following Table 2.

The roving (2) did not come in contact with the fixed opening pins (4)at all during the production of the foregoing reinforced strand (7). Asa result, there was not observed any fluffing and the connected portionsof the rovings (2) could satisfactorily pass through the multipleopening and resin-impregnation apparatus. However, the reason why theresulting reinforced strand (7) was insufficient in theresin-impregnation ability can be ascribed to the fact that the distancebetween the upper and lower stages of the fixed opening pins within themultiple apparatus (21) is too broad.

Comparative Example 11

The multiple opening and resin-impregnation apparatus (22) used in thisExample was such an apparatus that in the multiple apparatus (1) asshown in FIG. 12, the upper and lower of the fixed opening pins (4u and4d; 6 pins in all) were all removed while remaining three middle-stagefixed opening pins (4m1, 4m2 and 4m3) which were sandwiched between theupper-stage and lower-stage continuous fiber rovings (2u1) and (2d1).

Upper and lower-stage reinforced strands (7u1 and 7d1) were produced byrepeating the same procedures and conditions used in Example 12 exceptfor using the foregoing multiple apparatus (22). The resultingreinforced strands were finely cut into reinforced pellets (7) (averagelength: 10 mm), followed by subjecting the reinforced pellets (7) toinjection-molding to thus produce specimens according to the sameprocedures used in Example 11 under the same conditions used therein.

The resin-impregnation ability of the resulting reinforced strands (7)and the flexural strength of the specimen were determined and evaluated.As a result, the former was ranked as "not good" and the latter wasfound to be "129 MPa". On the other hand, the stable productivitythereof was judged to be "excellent". The results thus obtained aresummarized in the following Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Structure of multiple apparatus & roving-introduction system                  Upstream Opening pin       Downstream                                                                          Roving                                           side    No.            side     No.                                           turning                                                                            Pins/                                                                            of    Arrangement                                                                            turning                                                                             Pins/                                                                            of                                            pin  stage                                                                            st.                                                                              H/D                                                                              of pins                                                                             α°                                                                  pin   stage                                                                            stage                                     __________________________________________________________________________    Ex. 11                                                                            None 3  3   60                                                                              horizontal                                                                          -- None  6  2                                         Ex. 12                                                                            upper 1;                                                                           3  3   60                                                                              horizontal                                                                          -- None  6  2                                             lower 1                upper 1;                                                                            6  2                                         Ex. 13                                                                            None 3  3   60                                                                              horizontal                                                                          -- lower 1                                            Ex. 14                                                                            None 3  3   60                                                                              horizontal                                                                          40 None  6  2                                         Ex. 15                                                                            None 3  3   30                                                                              horizontal                                                                          -- None  6  2                                         Ex. 16                                                                            None 3  3  250                                                                              horizontal                                                                          -- None  6  2                                         Ex. 17                                                                            None 3  3  400                                                                              horizontal                                                                          -- None  6  2                                         Comp.                                                                             --   5  1  -- Zigzag                                                                              -- --    12 1                                         Ex. 1                                                                         Comp.                                                                             --   5  2  -- Zigzag                                                                              -- --    6  2                                         Ex. 6                                                                         Comp.                                                                             Upper 1,                                                                           -- -- -- --    -- None  6  2                                         Ex. 7                                                                             Lower 1                                                                   Comp.                                                                             None -- -- -- --    -- Upper 1,                                                                            6  2                                         Ex. 8                      Lower 1                                            Comp.                                                                             None 3  3   6 Horizontal                                                                          -- None  6  2                                         Ex. 9                                                                         Comp.                                                                             None 3  3  600                                                                              Horizontal                                                                          -- None  6  2                                         Ex. 10                                                                        Comp.                                                                             None 3  1  -- Horizontal                                                                          -- None  6  2                                         Ex. 11                                                                        __________________________________________________________________________                Physical properties of continuous fiber reinforced material                   Resin                                                                         impregnation                                                      Stable      ability   Flexural strength                                            productivity                                                                         (STRAND)  (STRAND)                                                                             (Pellet)                                         __________________________________________________________________________    Ex. 11                                                                             Excellent                                                                            Excellent Not determined                                                                       215                                              Ex. 12                                                                             Good   Excellent Not determined                                                                       222                                              Ex. 13                                                                             Good   Excellent 403    Not determined                                   Ex. 14                                                                             Excellent                                                                            Excellent Not determined                                                                       200                                              Ex. 15                                                                             Excellent                                                                            Excellent Not determined                                                                       224                                              Ex. 16                                                                             Excellent                                                                            Excellent Not determined                                                                       210                                              Ex. 17                                                                             Excellent                                                                            Good      Not determined                                                                       197                                              Comp.                                                                              Unacceptable                                                                          .sup. --*.sup.1                                                                         .sup. --*.sup.1                                                                      .sup. --*.sup.1                                 Ex. 1                                                                         Comp.                                                                              Unacceptable                                                                          .sup. --*.sup.1                                                                         .sup. --*.sup.1                                                                      .sup. --*.sup.1                                 Ex. 6                                                                         Comp.                                                                              Good   Unacceptable                                                                            Not determined                                                                       121                                              Ex. 7                                                                         Comp.                                                                              Good   Unacceptable                                                                            251    Not determined                                   Ex. 8                                                                         Comp.                                                                              Slightly bad                                                                         Excellent Not determined                                                                       216                                              Ex. 9                                                                         Comp.                                                                              Excellent                                                                            Slightly bad                                                                            Not determined                                                                       138                                              Ex. 10                                                                        Comp.                                                                              Excellent                                                                            Slightly bad                                                                            Not determined                                                                       129                                              Ex. 11                                                                        __________________________________________________________________________     Note:                                                                         *.sup.1 means that the property could not be determined since any molded      article could not be obtained, while "Not Determined" means that each         molded article could be produced, but each corresponding property was not     determined.                                                              

We claim:
 1. A method for producing a resin-impregnated structurereinforced by substantially unidirectionally aligned continuous fibers,the method comprising subjecting a substantially endless continuousfiber bundle to opening and impregnation with a molten resin, whereinthecontinuous fiber bundle is dipped in a bath of molten resin and thenpasses through a space between a pair of opening pins in the bath, thepins being positioned on sides of the bundle so that the continuousfibers are sandwiched by the pins without coming into contact witheither of the pins to thus subject the fibers of the bundle to openingand impregnation with the resin.
 2. The method as set forth in claim 1wherein the pair of opening pins comprise an upper-stage opening pin anda lower-stage opening pin, and wherein the space (H) between the upperand lower-stage opening pins and the average diameter (D) of individualfibers constituting the continuous fiber bundle satisfy the followingrelation:

    10D≦H≦500D.


3. 3. The method of claim 2 wherein the opening pins comprise anupper-stage opening pin and a lower-stage opening pin, and wherein thespace (H) is between the upper and lower-stage opening pins and theaverage diameter (D) of individual fibers constituting the continuousfiber bundle satisfy the following relation

    20D≦H≦300D.


4. The method of claim 1 wherein the opening pins comprise anupper-stage opening pin and a lower-stage opening pin, and wherein thespace (H) between the upper and lower-stage opening pins and the averagediameter (D) of individual fibers constituting the continuous fiberbundle satisfy the following relation:

    20D≦H≦300D.


5. A method for producing a columnar product composed of aresin-impregnated structure reinforced by substantiallyuni-directionally aligned continuous fibers, said method comprisingsubjecting a substantially endless continuous fiber bundle to openingand impregnation with a molten resin, wherein the continuous fiberbundle is dipped in a bath of a molten resin and simultaneously passesthrough a space between a pair of opening pins positioned on sides ofthe bundle so that the continuous fiber bundle is sandwiched by the pinswithout coming in contact with either of the pins to obtain aresin-impregnated structure reinforced with uni-directionally arrangedcontinuous fibers; and cutting the resulting resin-impregnated structureinto pieces having a desired length.
 6. An apparatus for producing aresin-impregnated structure reinforced by uni-directionally arrangedcontinuous fibers and having a resin penetrating between the fibers,wherein the apparatus comprises:a zone through which a molten resinformed from a molten resin-supply system flows, said molten resin beingsupplied to the zone through a pore and stored therein in apredetermined amount; an opening for introducing continuous fiberbundles, the opening positioned on an end wall or a top plate on anupstream side of the zone; at least one pair of opening pins which areapproximately vertically positioned within the zone at a predeterminedspace so that the continuous fiber bundle introduced into the zone isimmersed in the molten resin and can pass through a space formed betweenthe pair of pins without coming in contact with the pins; ashape-determining nozzle positioned on a downstream side and along themoving direction of the continuous fiber bundle to draw the fiber bundlepassing out of the zone, the bundle being introduced through a nozzleopening while passing through the space between the opening pins withoutcoming in contact with the pins; and a take-off system for thecontinuous fiber-reinforced resin structure drawn from theshape-determining nozzle.
 7. The production apparatus of claim 6 whereinthe at least one pair of opening pins comprise an upper-stage openingpin and a lower stage openining pin and the at least one pair of openingpins are provided at not less than three positions arranged along thedirection starting from the continuous fiber-introducing side towardsthe downstream side.
 8. The production apparatus of claim 7 wherein thespace (H) between the upper and lower-stage opening pins and the averagediameter (D) of individual fibers constituting the continuous fiberbundle satisfy the following relation:

    10D≦H≦500D.


9. The production apparatus of claim 7 wherein the space (H) between theupper and lower-stage opening pins and the average diameter (D) ofindividual fibers constituting the continuous fiber bundle satisfy thefollowing relation:

    20D≦H≦300D.


10. The production apparatus of claim 6 wherein the space (H) betweenthe upper and lower-stage opening pins and the average diameter (D) ofindividual fibers constituting the continuous fiber bundle satisfy thefollowing relation:

    10D≦H≦500D.


11. The production apparatus of claim 6 wherein the space (H) betweenthe upper and lower-stage opening pins and the average diameter (D) ofindividual fibers constituting the continuous fiber bundle satisfy thefollowing relation:

    20D≦H≦300D.


12. The production apparatus of claim 6 wherein at least three openingpins are approximately vertically arranged to form a group of openingpins and the group of opening pins are provided at not less than threepositions arranged along the direction starting from the continuousfiber-introducing side towards the downstream side.
 13. The productionapparatus of claim 12 wherein the space (H) between two fixed openingpins in the group of the fixed opening pins, through which thecontinuous fiber bundle passes, and the average diameter (D) ofindividual fibers constituting the continuous fiber bundle satisfy thefollowing relation:

    10D≦H≦500D.


14. The production apparatus of claim 12 wherein the space (H) betweentwo fixed opening pins in the group of the fixed opening pins, throughwhich the continuous fiber bundle passes, and the average diameter (D)of individual fibers constituting the continuous fiber bundle satisfythe following relation:

    20D≦H≦300D.


15. An apparatus for producing a continuous resin-impregnated structurereinforced by uni-directionally arranged continuous fibers and having aresin penetrating between the fibers, wherein the apparatus comprises:azone through which a molten resin formed from a molten resin-supplysystem flows, said molten resin being supplied to the zone through apore and stored therein in a predetermined amount; at least two openingsfor introducing continuous fiber bundles, the openings positioned on anend wall or a top plate arranged on the upstream side of the zone; atleast three opening pins which are approximately perpendicularlypositioned within the zone at predetermined spaces to form a group offixed opening pins so that the continuous fiber bundles introduced intothe zone are immersed in the molten resin and pass through a spaceformed between the pins without coming in contact with the pins; ashape-determining nozzle positioned on a downstream side and along themoving direction of the continuous fiber bundles so as to draw the fiberbundles passing out of the zone, the fiber bundles being introducedthrough nozzle openings while passing through the spaces between theopening pins without coming into contact with the pins; and a take-offsystem for the continuous fiber-reinforced resin structure drawn fromthe shape-determining nozzle.
 16. The production apparatus of claim 15wherein the space (H) between two fixed opening pins in the group of thefixed opening pins, through which the continuous fiber bundle passes,and the average diameter (D) of individual fibers constituting thecontinuous fiber bundle satisfy the following relation:

    10D--H--500D.


17. The production apparatus of claim 15 wherein the space (H) betweentwo fixed opening pins in the group of the fixed opening pins, throughwhich the continuous fiber bundle passes, and the average diameter (D)of individual fibers constituting the continuous fiber bundle satisfythe following relation:

    20D≦H≦300D.